Li2MnO3-LiMO2-连芳

废旧锂离子电池回收制备MnO_(2)及其储锌性能彭雪;刘培艳;夏铭;刘媛媛【期刊名称】《洁净煤技术》【年(卷),期】2024(30)2【摘要】随着锂离子电池产业的快速发展,退役锂离子电池的回收利用问题已成为工业和学术界关注的热点。

前人对废旧锂离子电池中有价值资源的回收做了大量研究,但将回收的锂离子电池材料直接转化为新型储能体系电极材料的研究鲜有报道。

为实现退役电池的资源化再利用,可通过简单的H_(2)SO_(4)浸渍法,将废旧锂离子电池中锰酸锂(LiMn_(2)O_(4))材料转化为MnO_(2),并用做水系锌离子电池正极材料。

通过XRD、XPS、BET、SEM、CV、TEM、EIS以及电化学性能测试等表征方法,探究酸浸渍条件如温度、时间等对所制备MnO_(2)形貌、结构和电化学性能的影响规律。

结果表明:LiMn2O4材料经酸浸渍会发生歧化反应,使Li^(+)和部分Mn^(2+)从晶格中溶出,而浸渍温度对离子的溶出速度有显著影响。

室温下,LiMn_(2)O_(4)晶格中离子的溶出速度较慢,可获得与其晶体结构相近的λ-MnO_(2)材料;而水热条件下,高反应温度会加剧晶格中原子的振动,加快离子溶出速度,形成晶体结构更紧密且热力学更稳定的γ-MnO_(2)和β-MnO_(2)。

电化学性能测试结果显示,具有纳米棒状形貌和较大比表面积的γ-MnO_(2)材料,表现出较高的放电比容量和最优的循环稳定性,在0.3和3.0 A/g电流密度下,其放电比容量分别为273.3和127.2 mAh/g。

在3.0 A/g电流密度下,γ-MnO_(2)材料经200、500和1 000圈循环后,其容量保持率高达77.1%、65.7%和43.9%。

此外,通过ex-XRD表征研究发现,该Zn//MnO2电池的电化学储能机理遵循H+/Zn2+共插入/脱出机制。

【总页数】10页(P209-218)【作者】彭雪;刘培艳;夏铭;刘媛媛【作者单位】烟台大学化学化工学院;南京工业大学化工学院【正文语种】中文【中图分类】TQ152【相关文献】1.以废旧锌锰电池为锰源制备锂离子电池正极材料LiMn2O42.用于回收废旧锂离子电池中Co(Ⅱ)的2种新型螯合剂的制备及其性能3.废旧锌锰电池回收制备菱形三氧化二锰及其对染料吸附性能研究4.从废旧锂离子电池中回收制备LiCoO_2的结构与性能研究5.低温水浴法制备钾离子预嵌层状MnO_(2)及其储锌性能因版权原因，仅展示原文概要，查看原文内容请购买。

Electrochemical and Structural Properties of x Li2M′O3‚(1-x)LiMn0.5Ni0.5O2Electrodes for Lithium Batteries(M′)Ti,Mn,Zr;0e x E0.3)Jeom-Soo Kim,Christopher S.Johnson,John T.Vaughey,andMichael M.Thackeray*Electrochemical Technology Program,Chemical Engineering Division,Argonne National Laboratory,Argonne,Illinois60439Stephen A.HackneyDepartment of Metallurgical and Materials Engineering,Michigan Technological University,Houghton,Michigan49931Wonsub YoonBrookhaven National Laboratory,Upton,New York11973Clare P.GreyDepartment of Chemistry,State University of New York,Stony Brook,New York11794 Received December24,2003.Revised Manuscript Received March4,2004Electrochemical and structural properties of x Li2M′O3‚(1-x)LiMn0.5Ni0.5O2electrodes(M′)Ti,Mn,Zr;0e x e0.3)for lithium batteries are reported.Powder X-ray diffraction,lattice imaging by transmission electron microscopy,and nuclear magnetic resonance spectroscopy provide evidence that,for M′)Ti and Mn,the Li2M′O3component is structurally integrated into the LiMn0.5Ni0.5O2component to yield“composite”structures with domains having short-range order,rather than true solid solutions in which the cations are uniformly distributed within discrete layers.Li2TiO3and Li2ZrO3components are electrochemically inactive, whereas electrochemical activity can be induced into the Li2MnO3component above4.3V vs Li0.When cycled in lithium cells,x Li2MnO3‚(1-x)LiMn0.5Ni0.5O2electrodes with x)0.3 provide capacities in excess of300mA‚h/g over the range4.6-1.45V.IntroductionLayered lithium transition-metal-oxide electrodes Li x-MO2(M)Co,Ni,and Mn)become unstable at low lithium content when lithium cells are charged above 4.3V.At this potential,the oxygen activity at the electrode surface is increased to a level at which side reactions can occur,such as electrolyte oxidation or oxygen loss.For several years,following the discovery that acid treatment of Li2MnO3produces a novel layered Li2-x MnO3-x/2structure,1which on relithiation yields a compound that can be formulated as x Li2M′O3‚(1-x)-LiMO22(ignoring the H+ion exchange that occurs during acid treatment),1,3we have pursued an approach using an electrochemically inactive Li2M′O3component (e.g.,Mn,Ti,or Zr)to stabilize these layered LiMO2 structures.In particular,we have used this approach in attempts to prevent the conversion of layered LiMnO2 to spinel.4,5Our efforts to stabilize layered LiMn1-x Ni x O2electrodes followed reports by Pacific Lithium Ltd.that Li1.2Mn0.4Cr0.4O2electrodes(alternatively,x Li2MnO3‚(1-x)LiCrO2[M′)Mn;M)Cr;x)0.5])provided high capacity and good cycling stability at50°C when cells were charged and discharged between4.4and2.5V.6,7 Our more recent efforts were influenced by reports that LiMn0.5Ni0.5O2and related lithium manganese-nickel oxides can provide capacities reaching200mA‚h/g.8-11 In particular,our approach is similar to that of Dahn et al.10who have studied the Li[Ni x Li(1/3-2x/3)Mn(2/3-x/3)]O2 system(0<x<0.5),which can be written,alternatively, in composite notation as(1-2x)Li2MnO3‚(3x)LiMn0.5-*To whom correspondence should be addressed.Email:thackeray@ .(1)Rossouw,M.H.;Thackeray,M.M.Mater.Res.Bull.1991,26,463.(2)Rossouw,M.H.;Liles,D.C.;Thackeray,M.M.J.Solid State Chem.1993,104,464.(3)Tang,W.;Kanoh,H.;Yang,X.;Ooi,K.Chem.Mater.2000,12, 3271.(4)Johnson,C.S.;Korte,S.D.;Vaughey,J.T.;Thackeray,M.M.; Bofinger,T.E.;Shao-Horn,Y.;Hackney,S.A.J.Power Sources1999, 81-82,491.(5)Johnson,C.S.;Thackeray,M.M.The Electrochem.Soc.Inc., PV2000-36,2001,47.(6)Ammundsen,B.;Desilvestro,J.;Steiner,R.;Pickering,P.10th International Meeting on Lithium Batteries,Como,Italy,28May-2 June2000;Ext.Abstr.No.17.(7)Ammundsen,B.;Paulsen,J.Adv.Mater.2001,13,943.(8)Spahr,M.E.;Novak,P.;Schnyder,B.;Haas,O.;Nesper,R.J. Electrochem.Soc.1998,14,1113.(9)Ohzuku,T.;Makimura,Y.Chem.Lett.2001,744.(10)Lu,Z.;MacNeil,D.D.;Dahn,J.R.Electrochem.Solid State Lett.2001,4,A191.(11)Lu,Z.;Dahn,J.R.J.Electrochem.Soc.2002,149,A815.1996Chem.Mater.2004,16,1996-200610.1021/cm0306461CCC:$27.50©2004American Chemical SocietyPublished on Web04/20/2004Ni0.5O2(also for0<x<0.5).During the course of ourstudies,it was discovered that LiMn0.5Ni0.5O2andcomposite x Li2M′O3‚(1-x)LiMn0.5Ni0.5O2(M)Mn,Ti)electrode structures could accommodate an additionallithium within their structures at approximately1.5Vvs Li0without disturbing the layered transition-metalframework structure.12,13This reaction,which is revers-ible,greatly increases the capacity of the layeredelectrode.The structures of x Li2M′O3‚(1-x)LiMO2compounds(alternatively,in layered notation,Li(2+2x)/(2+x)M′2x/(2+x)-M(2-2x)/(2+x)O2)appear to be complex.For example,magicangle spinning(MAS)nuclear magnetic resonance(NMR)and X-ray absorption spectroscopy(XAS)dataof Li1.2Mn0.4Cr0.4O2electrodes(Li2MnO3‚LiCrO2)haveprovided evidence that the Li2MnO3and LiCrO2com-ponents do not form a random solid solution,but ratherthat the structures tend to have short-range order withlocal clustering of the lithium and transition-metalions.14,15Li2MnO3-like local environments or smalldomains were observed by NMR,which were electro-chemically inert.15Similar Li2MnO3-like local environ-ments were seen for Li[Ni x Li(1/3-2x/3)Mn(2/3-x/3)]O2for0e x e0.5,but the Li ions in these environments participated in the electrochemistry,suggesting that thedomains were smaller in size.16However,Dahn et al.17recently opposed the idea of Li2MnO3-like domains fromanalyses of XRD data and argued that the cations arearranged homogeneously within the layers of Li[Cr x-Li(1-x)/3Mn(2-2x)/3]O2for0e x e1(alternatively,(2-2x)-Li2MnO3‚(3x)LiCrO2)and Li[Ni x Li(1/3-2x/3)Mn(2/3-x/3)]O2for0e x<0.5(alternatively,(1-2x)Li2MnO3‚(3x)LiMn0.5-Ni0.5O2)structures,suggesting“a true solid solution phase.”In this paper,we address the ordering of these materials.For simplicity,we restrict the definition of structures in this paper,in most instances,to the composite notation x Li2M′O3‚(1-x)LiMO2rather than the equivalent layered notations used by Dahn et al.10 We define and discuss x Li2M′O3‚(1-x)LiMn0.5Ni0.5O2 electrode structures(M′)Mn,Ti,or Zr;0e x e0.3)as determined by powder X-ray diffraction(XRD),high-resolution transmission electron microscopy(HRTEM), and MAS NMR.Electrochemical properties of the electrodes at both high potential(4.6-2.0V)and at low potential(2.0-1.0V)vs a metallic lithium reference electrode are presented.The electrochemical properties of electrodes containing a Li2MnO3component are interpreted with reference to reports of the electro-chemical activity that can be induced into Li2MnO3by acid treatment1,18or by charging Li2MnO3electrodes directly in lithium cells.19To facilitate a discussion of the results,we first consider the structures of x Li2M′O3‚(1-x)LiMO2elec-trodes.Because of the structural similarities between Li2M′O3-and LiMO2-type compounds,it was proposed several years ago that it might be possible to use an electrochemically inactive Li2M′O3component,such as Li2MnO3,Li2TiO3,or Li2ZrO3,to stabilize LiMO2inser-tion electrodes(M)Co,Ni,Mn,and combinations thereof),particularly at low lithium loadings,by forming “composite”electrode structures,x Li2M′O3‚(1-x)Li-MO2.2,4,20,21In LiCoO2,LiNiO2,and LiMnO2,the lithium and transition-metal ions are located in octahedral sites in alternating layers(Figure1a),whereas in Li2MnO3 and Li2TiO3(in layered notation,Li[Li0.33Mn0.67]O2and Li[Li0.33Ti0.67]O2,respectively),one-third of the transi-tion-metal ions are replaced by lithium(Figure1b).22 In Li2ZrO3,the structure is not layered because each cation layer contains Li+and Zr4+ions in a2:1ratio (Figure1c).23The composition of x Li2M′O3‚(1-x)LiMO2electrodes for the complete range of x(0e x e1)is defined by the Li2M′O3-LiMO2tie-line in the schematic phase diagram of the Li2M′O3-MO2-LiMO2-Li2MO2system in Figure 2.In ideal layered Li2M′O3and LiMO2structures,such as Li2MnO3and LiCoO2,respectively,the cations in the transition-metal layers are perfectly ordered in layers between close-packed oxygen planes.Cation ordering(12)Johnson, C.S.;Kim,J.-S.;Kropf, A.J.;Kahaian, A.J.; Vaughey,J.T.;Thackeray,mun.2002,4,492.(13)Johnson, C.S.;Kim,J.-S.;Kropf, A.J.;Kahaian, A.J.; Vaughey,J.T.;Fransson,L.M.;Edstrom,K.;Thackeray,M.M.Chem. Mater.2003,15,2313.(14)Ammundsen,B.;Paulsen,J.;Davidson,I.;Liu,R.-S.;Shen,C.-H.;Chen,J.-M.;Jang,L.-Y.;Lee,J.-F.J.Electrochem.Soc.2002, 149,A431.(15)Pan,C.J.;Lee,Y.J.;Ammundsen,B.;Grey,C.P.Chem.Mater.2002,14,2289.(16)Yoon,W.S.;Paik,P.;Yang,X.-Q.;Balasubramanian,M.; McBreen,J.;Grey,C.P.Electrochem.Solid State Lett.2002,5,A263.(17)Lu,Z.;Chen,Z.;Dahn,J.R.Chem.Mater.2003,15,3214.(18)Paik,Y.;Grey,C.P.;Johnson,C.S.;Kim,J.-S.;Thackeray, M.M.Chem.Mater.2002,14,5109.(19)Robertson,A.D.;Bruce,P.G.Chem.Mater.2003,15,1984.(20)Kim,J.-S.;Johnson,C.S.;Thackeray,M.M.Electrochem. Commun.2002,4,205.(21)Johnson,C.S.;Thackeray,M.M.In Proc.198th ECS Meeting, Phoenix,AZ,2000;Abstr.No.67.(22)Strobel,P.;Lambert,A.B.J.Solid State Chem.1988,75,90.(23)Hodeau,J.L.;Marezio,M.;Santoro,A.;Roth,R.S.J.Solid State Chem.1982,45,170.Figure1.Schematic illustrations of the structures of(a) LiMO2(M)Mn,Ni,Co);(b)Li2MnO3and Li2TiO3;(c)Li2-ZrO3;(d)Li2MO2(M)Mn,Ni).positional phase diagram of the Li2MnO3-MO2-LiMO2-Li2MO2system.xLi2M′O3‚(1-x)LiMn0.5Ni0.5O2for Li Batteries Chem.Mater.,Vol.16,No.10,20041997occurs in the Li2Mn layers of Li2MnO3,which is drivenby the large differences in charge of the monovalent andtetravalent Li and Mn ions,respectively.Therefore,when synthesizing compounds that fall on a Li2M′O3-LiMO2tie-line,it seems highly unlikely that perfectlyordered structures or superstructures with a homoge-neous distribution of monovalent,divalent,trivalent,and/or tetravalent cations in the transition-metal layerswill result,except at certain crystallographically allowedvalues of x.Furthermore,because it is extremely dif-ficult to control the precise stoichiometry of lithiatedmetal oxide products at high synthesis temperatures,it is also highly likely that there will be variations inlocal composition in their structures,the extent of whichwill be dependent on(1)localized concentrations oflithium and transition-metal ions at the time of syn-thesis,(2)the oxygen content of the sample,and(3)thefree energy of formation of various thermodynamicallyfavored phases that will compete with one another atthe synthesis temperature.The LiMn0.5Ni0.5O2structure that has been used asthe LiMO2component in the x Li2M′O3‚(1-x)LiMn0.5-Ni0.5O2composite electrodes(M′)Mn,Ti,or Zr;0e xe0.3)of this investigation is of particular interest because the manganese and nickel ions adopt tetrava-lent and divalent oxidation states,respectively,ratherthan a trivalent state.10(Note that both Mn3+(d4)andNi3+(d7)ions are Jahn-Teller active and that relaxationto undistorted states can therefore be achieved simul-taneously by electron transfer from a Mn3+ion to aneighboring Ni3+ion.)Because manganese and nickelions exist in the transition-metal layers of the LiMn0.5-Ni0.5O2structure in a1:1ratio,there is no simple3-fold(point group)symmetry in the transition-metal layersas there is in Li2MnO3.It is therefore impossible forevery nickel ion to be surrounded by six manganese ionsand vice versa.Therefore,if an ordered structure exists,there has to be another arrangement of the nickel andmanganese ions.24Ceder et al.25have predicted by first-principles calculations that a zigzag arrangement ofnickel and manganese has the lowest formation energy.However,no experimental crystallographic data has,toour knowledge,been provided that confirms the exist-ence of the zigzag phase,presumably in part becausematerials synthesized to date contain Li ions in additionto Ni and Mn ions in the predominantly transition-metallayers.Yoon et al.16,26have demonstrated by MAS NMRthat even in a LiMn0.5Ni0.5O2sample evidence could befound of local clustering and cation ordering in thetransition-metal layers(i.e.,Li2MnO3-type character),which was consistent with the presence of Ni ions inthe lithium layers and vice versa,which is common inlayered lithium-nickel oxides.27The spectra were ra-tionalized by using a model based on Li2MnO3-likeordering,the Ni2+substituting in sites that minimizethe number of Li+-Ni2+contents in the transition-metal layers.28Some evidence for Ni2+clustering,presumablyin LiNi0.5Mn0.5O2regions,was also observed for0.3e x <0.5.28Ohzuku has predicted by first-principles calculationsthat a 3× 3supercell should exist in a LiMn0.33-Ni0.33Co0.33O2structure.29Dahn et al.17claim fromanalyses of powder X-ray diffraction data that a similar 3× 3supercell exists for Li[Ni x Li(1/3-2x/3)Mn(2/3-x/3)]O2 samples(0<x e0.5)(alternatively,(1-2x)Li2MnO3‚(3x)LiMn0.5Ni0.5O2)but assert that because the latticeparameters change continuously with x,the cations arehomogeneously distributed in the transition-metal lay-ers over a wide range of x.During our initial studies of LiMn0.5Ni0.5O2and0.03Li2TiO3‚0.97LiMn0.5Ni0.5O2electrodes,it was dis-covered that an additional lithium ion could be insertedinto the LiMn0.5Ni0.5O2component below2V vs Li0toyield a Li2Mn0.5Ni0.5O2structure without destroying thelayered arrangement of the electrode structure(Figure1d).12,13In Li2Mn0.5Ni0.5O2,which is isostructural withLi2MnO230and Li2NiO2,31the manganese and nickelions maintain their octahedral configuration,whereasthe lithium ions fully occupy the tetrahedral sites inadjacent layers.The Li2MO2composition is included inthe compositional phase diagram in Figure2because,in principle,such structures can significantly increasethe capacity of composite x Li2M′O3‚(1-x)LiMO2elec-trodes at potentials below2V vs Li0.Experimental SectionSynthesis of x Li2M′O3‚(1-x)LiMn0.5Ni0.5O2Electrodes. Electrode materials defined by the general composition x Li2M′O3‚(1-x)LiMn0.5Ni0.5O2(M′)Ti,Mn,and Zr)were prepared for x)0.03,0.07,0.14,and0.30.Electrodes in which M′)Ti or Zr were prepared by reacting the appropriate amounts of anatase(TiO2,Aldrich),titanium isopropoxide(Ti-[OCH(CH3)2]4,Aldrich),or zirconium isopropoxide2-propanol complex(Zr[OCH(CH3)2]4‚(CH3)2CHOH,Aldrich)with lithium hydroxide monohydrate(LiOH‚H2O,Aldrich)and Ni0.5Mn0.5-(OH)2.Electrodes in which M′)Mn were prepared directly from Ni1-x Mn x(OH)2and LiOH‚H2O using the required Li:Mn: Ni ratio.The Ni0.5Mn0.5(OH)2and Ni1-x Mn x(OH)2precursors were prepared in-house by precipitation from a basic LiOH solution of Ni(NO3)2and Mn(NO3)2(pH∼11).The reagents were intimately mixed in an acetone slurry,dried in an oven overnight,and subsequently fired at480°C for12h and then at900°C for10h in air.Thereafter,the samples were rapidly quenched(also in air).Powder X-ray diffraction patterns of the products were collected on a Siemens D5000powder diffractometer with Cu K R radiation between10°and80°2θat a scan rate of0.6°2θ/ttice parameters of the phases were determined by Rietveld profile refinements of the X-ray diffraction patterns.High-Resolution Transmission Electron Microscopy. High-resolution images of x Li2TiO3‚(1-x)LiMn0.5Ni0.5O2and x Li2MnO3‚(1-x)LiMn0.5Ni0.5O2structures were obtained for x )0,0.14,and0.30.Samples were prepared for the electron microscope by a standard procedure described elsewhere.32The images were collected on a JEOL-JEM4000FEX-1transmis-(24)Islam,M.S.;Davies,R.A.;Gale,J.D.Chem.Mater.2003,15, 4280.(25)Ceder,G.;Carlier,D.;Grey,C.P.;Gorman,J.P.;Reed,J. Lithium Battery Discussion Workshop,Arcachon,France,14-19 September2003;Ext.Abstr.No.53.(26)Yoon,W.-S.;Grey,C.P.;Balsubramanian,M.;Yang,X.-Q.; McBreen,J.Chem.Mater.2003,15,3161.(27)Delmas,C.In Lithium Batteries,New Materials,Developments, and Perspectives;Pistoia,G.,Ed.;Elsevier:Amsterdam,1994; p457.(28)Yoon,W.-S.;Iannopollo,S.;Grey,C.P.;Carlier,D.;Gorman, J.;Reed,J.;Ceder,G.Electrochem.Solid State Lett.,in press.(29)Koyama,Y.;Tanaka,I.;Adachi,H.;Makimura,Y.;Ohzuku, T.J.Power Sources2003,119-121,644.(30)David,W.I.F.;Goodenough,J.B.;Thackeray M.M.;Thomas, M.G.S.R.Rev.Chem.Miner.1983,20,636.(31)Dahn,J.R.;von Sacken,U.;Michal,C.A.Solid State Ionics 1990,44,87.(32)Shao-Horn,Y.;Hackney,S.A.;Cornilsen,B.C.J.Electrochem. Soc.1997,144,3147.1998Chem.Mater.,Vol.16,No.10,2004Kim et al.sion electron microscope under an accelerating voltage of200 keV.The images were produced without an objective aperture to produce phase contrast.Fourier transform analysis was carried out using Scion Image(Scion Corp.,Release Beta4.0.2) on a64×64pixel section of the digital image file.Magic Angle Spinning Nuclear Magnetic Resonance. 6Li MAS NMR data of x Li2TiO3‚(1-x)LiMn0.5Ni0.5O2samples (x)0,0.14,and0.30)were collected at29.5MHz on a CMX-200spectrometer,with a spinning speed of38kHz and rotor synchronized spin-echoes(π/2-τ-π-τ-acq.;τ)one rotor period;π/2)2µs).The spectra were referenced to1M LiCl at0ppm.Electrochemical Measurements.Electrodes were fabri-cated by intimately mixing85wt%of the appropriate x Li2M′O3‚(1-x)LiMn0.5Ni0.5O2powder,8wt%poly(vinylidenedifluoride)(PVDF)binder(Kynar,Elf-Atochem),and7wt% acetylene black(Cabot)in a1-methyl-2-pyrrolidinone(NMP) solvent(Aldrich,99+%).The mixed slurry was cast onto an aluminum foil current collector and dried at75°C for3-5h. The electrode laminates were dried further at70°C under vacuum overnight.Disk electrodes with an area of1.6cm2 were punched from the laminates.The electrodes were evalu-ated in coin-type cells(size2032,Hohsen Corp.)with lithium foil(FMC Corp.)as the counter electrode,a polypropylene separator(Celgard),and an electrolyte solution consisting of 1M LiPF6in a1:1ethylene carbonate:diethyl carbonate solvent mixture(Merck).Cells were constructed inside a helium-filled glovebox(<5ppm,H2O and O2).Cells were cycled galvanostatically using a Maccor Series2000control unit at a current rate of0.1mA/cm2.ResultsXRD Patterns.The powder XRD patterns of x Li2-M′O3‚(1-x)LiMn0.5Ni0.5O2electrodes for M′)Mn,Ti, or Zr and0e x e0.3are provided in Figure3.Because of the paucity of data,lattice parameters were refined using the high-symmetry trigonal space group,R3h m, rather than the low-symmetry monoclinic space group, C2/m,to monitor the variations in unit cell dimensions as a function of composition,x(Table1).The XRD patterns of the x Li2MnO3‚(1-x)LiMn0.5Ni0.5O2(x)0.00, 0.03,0.14,and0.30)composite structures in Figure3a are similar.Figure3a shows a slight increase in intensity of the peaks at20-23°2θas the Li2MnO3 component in the structure increases,which is consis-tent with an increasing amount of lithium in the transition-metal layers.Our XRD patterns and the changes in lattice parameter are consistent with those reported by Dahn et al.17for Li[Ni x Li(1/3-2x/3)Mn(2/3-x/3)]O2 electrodes;the smooth variation in lattice parameter with composition was interpreted by this group as suggesting that these materials are structurally and chemically homogeneous.Overall,the average unit cell parameters and unit cell volumes decrease marginally with increasing Mn content,which is consistent with the difference in the ionic radii between Mn4+(0.54Å) and Ni2+(0.69Å)ions in octahedral coordination.33By contrast,the average lattice parameters and unit cell volumes of x Li2TiO3‚(1-x)LiMn0.5Ni0.5O2products syn-thesized from a Ti[OCH(CH3)2]4precursor increase in value with increasing x;in this case,the trend is consistent with the larger ionic radius of Ti4+(0.61Å) compared to Mn4+(0.54Å).The patterns in Figure3a,b emphasize the structural compatibility that exists among Li2MnO3,Li2TiO3,and LiMn0.5Ni0.5O2phases and the ability of the Li2M′O3-type component to become inte-grated into a LiMO2-type structure.However,when TiO2(anatase)was used as a precursor,the XRD patterns of the x Li2TiO3‚(1-x)LiMn0.5Ni0.5O2products showed two-phase character,which is clearly noticeable, for x)0.3,at approximately44°2θin Figure3c, suggesting that the Li2TiO3component is not integrated to the same extent into the LiMn0.5Ni0.5O2structure as it is in the products in Figure3b.This observation clearly emphasizes that the structural integration of Li2M′O3and LiMn0.5Ni0.5O2components depends strongly on the type of reagents used and on the reaction conditions during synthesis.The X-ray diffraction patterns of x Li2ZrO3‚(1-x)-LiMn0.5Ni0.5O2products showed that the LiMn0.5Ni0.5O2 structure is less tolerant to accommodating Li2ZrO3. Although the0.03Li2ZrO3‚0.97LiMn0.5Ni0.5O2electrode had an X-ray diffraction pattern similar to those of its M′)Mn and Ti analogues(Figure3d),x Li2ZrO3‚(1-x)LiMn0.5Ni0.5O2products with higher Li2ZrO3content (x>0.03)were multiphase,as were those of x Li2MnO3‚(1-x)LiMn0.5Ni0.5O2and x Li2TiO3‚(1-x)LiMn0.5Ni0.5O2 products for x>0.3(not shown).We are unsure of the structural features of0.03Li2ZrO3‚0.97LiMn0.5Ni0.5O2, and we do not know yet if,at this low concentration, the Li2ZrO3component is embedded within the bulk of the LiMn0.5Ni0.5O2structure or whether it exists as an independent phase.We attribute the difficulty in inte-grating Li2ZrO3into a layered LiMn0.5Ni0.5O2structure to(1)the absence of lithium layering in Li2ZrO3(Figure 1c)and(2)the relatively large second-row transition-metal ion,Zr4+(ionic radius)0.72Å).33Although refinements of the XRD patterns showed that the lattice parameters of both x Li2MnO3‚(1-x)-LiMn0.5Ni0.5O2and x Li2TiO3‚(1-x)LiMn0.5Ni0.5O2sys-tems changed gradually with x,which is consistent with increasing amounts of Li2MnO3and Li2TiO3,respec-tively,X-ray diffraction is not a sufficiently sensitive technique for determining the local variations in com-position and structure in these materials.We therefore relied on more sensitive techniques,such as HRTEM and NMR,to obtain a more detailed understanding of the local structure of these materials at a nanoscopic level.HRTEM Analyses.The HRTEM images of struc-tures in the x Li2MnO3‚(1-x)LiMn0.5Ni0.5O2and x Li2-TiO3‚(1-x)LiMn0.5Ni0.5O2systems were examined at three compositions,x)0.0,0.14,and0.30.To accom-modate the diffraction peaks that occur between20°and 23°2θin the XRD patterns of these compounds,the indexing of the lattice fringes was based on the mono-(33)Shannon,R.D.;Prewitt,C.T.Acta Crystallogr.1969,B25, 925.ttice Parameters ofx Li2M′O3‚(1-x)LiMn0.5Ni0.5O2Structures(M′)Mn,Ti,Zr) x a(Å)c(Å)vol(Å3)x Li2MnO3‚(1-x)LiMn0.5Ni0.5O20.03 2.870(1)14.259(3)101.69(2)0.14 2.864(1)14.246(2)101.21(2)0.30 2.859(1)14.246(2)100.85(2)x Li2TiO3‚(1-x)LiMn0.5Ni0.5O20.03 2.876(1)14.274(2)102.22(1)0.14 2.881(1)14.304(2)102.78(2)0.30 2.887(1)14.342(2)103.52(2)x Li2ZrO3‚(1-x)LiMn0.5Ni0.5O20.03 2.873(1)14.259(2)101.94(2)xLi2M′O3‚(1-x)LiMn0.5Ni0.5O2for Li Batteries Chem.Mater.,Vol.16,No.10,20041999clinic unit cell (C 2/m )defined by Strobel et al.22for Li 2-MnO 3.The examination of the X-ray diffraction patterns of these materials shows the same type of “superlattice”peaks between 20°and 23°2θas described by Dahn et al.17for the Li[Ni x Li (1/3-2x /3)Mn (2/3-x /3)]O 2system (0<x <0.5).These peaks are of particular importance to the local (nearest cation neighbor)environment of the Li ions because the peak intensities are a rationalization of the ordering of the lithium,manganese,and other transition-metal ions present in the transition-metal layers.However,an ideal superlattice can occur only if the atomic distribution is uniform on a length scale approaching that of the superlattice length and if the ions occur in exactly the correct proportion.When such an ideal superlattice occurs,it is expected that the broadening of the superlattice peaks will correspond to the same crystallite size as that determined from “nonsuperlattice”peaks.If,however,the composition is nonideal in the sense that it deviates from that required by an ideal superlattice,or if the composition is not spatially uniform,then the superlattice peaks will be weakened and broadened.34This is of specific concern to this work because of the observations ofrelativelyFigure 3.Powder X-ray diffraction patterns of x Li 2M ′O 3‚(1-x )LiMn 0.5Ni 0.5O 2structures:(a)x Li 2MnO 3‚(1-x )LiMn 0.5Ni 0.5O 2(x )0.0,0.03,0.14,0.30);(b)x Li 2TiO 3‚(1-x )LiMn 0.5Ni 0.5O 2(x )0.03,0.14,0.30)(Ti[OCH(CH 3)2]4precursor);(c)x Li 2TiO 3‚(1-x )LiMn 0.5-Ni 0.5O 2(x )0.03,0.14,0.30)(TiO 2precursor);(d)x Li 2ZrO 3‚(1-x )LiMn 0.5Ni 0.5O 2(x )0.03).2000Chem.Mater.,Vol.16,No.10,2004Kim et al.broad superlattice lines in the nonideal compound compositions,for example,x Li 2M ′O 3‚(1-x )LiMO 2com-positions x )0.14and x )0.30.In such cases,where relatively broad superlattice peaks are observed,two different structural models can be used to rationalize the observation.We may consider either (1)that the broadening is due to isolated regions of composition close to what is ideal for superlattice formation surrounded by disordered regions of nonideal composition 35or (2)that the composition is uniform,but that the ordered structure is interrupted by anti-phase domain bound-aries.36In either case,there will be variations in the local environment of Li compared to the ideal superlat-tice.We therefore resorted to HRTEM to provide further evidence for the existence of such nonuniformities in the superlattice,as suggested by the broadening of the superlattice peaks in Figure 3a,ing this technique,it is possible to directly image the superlattice structure corresponding to the peaks at 20-23°2θ.Figure 4a shows the lattice fringes of a LiMn 0.5Ni 0.5O 2structure associated with the close-packed 001planes of the monoclinic unit cell (d ≈ 4.7Å),which are equivalent to the 003planes of the trigonal (R 3h m )unit cell of LiCoO 2.The image shows well-behaved packing of these planes,as might be expected in a stoichiometric LiMn 0.5Ni 0.5O 2structure.However,if the crystals are at orientations that allow the possibility of coherentdiffraction from the superlattice structure,then fringes of weak contrast and discontinuous morphology corre-sponding to the “superlattice”peaks at 20-23°2θ(i.e.,the (020)and (110)peaks,d ≈4.3Å)are observed within a single grain of LiMn 0.5Ni 0.5O 2(Figure 4b).The nanoscale,spatial variation in the lattice fringe contrast suggests that,even in the parent LiMn 0.5Ni 0.5O 2struc-ture,the distribution of the cations in the transition-metal layers is not random or homogeneous.We also note that the existence of the discontinuous superlattice structure for LiMn 0.5Ni 0.5O 2observed here by HRTEM is indeed consistent with the MAS NMR results,16,26but would be difficult to predict using isolated X-ray dif-fraction spectra.In an attempt to have a more quantitative measure of the structure and chemistry variations suggested in Figure 4b,two adjacent areas are circled in Figure 4b for specific consideration.Qualitatively,it is observed that the lattice fringes corresponding to the superlattice structure show greater definition in region (i)compared to region (ii).This observation is relevant because the amplitude of contrast of the lattice fringes is propor-tional to the superlattice structure factor.37Assuming that the crystallographic orientation and crystal thick-ness are approximately the same for these adjacent regions,the variation in lattice fringe contrast implies a spatial variation in the structure factor for the superlattice.A more quantitative demonstration of the(34)Guinier,A.X-ray Diffraction ;W.H.Freeman and Company:San Francisco,CA,1963;p 254.(35)Rhines,F.M.;Newkirk,J.B.Trans.ASM 1953,45,1029.(36)Jones,F.W.;Sykes,G.Proc.R.Soc.London A 1938,166,376.(37)Williams,D.B.;Carter,C.B.Transmission Electron Micros-copy ;Plenum Press:New York,1996;p441.Figure 4.(a)LiMn 0.5Ni 0.5O 2lattice fringes associated with (001)peak (C 2/m ).(b)HRTEM image of LiMn 0.5Ni 0.5O 2formed using phase contrast from superlattice peaks and local fast Fourier transforms (inset)from adjacent areas (i)and (ii)to emphasize the spatial variation in superlattice order parameter.(c)HRTEM image of 0.30Li 2MnO 3‚0.70LiMn0.5Ni 0.5O 2formed using phase contrast from superlattice peaks and fast Fourier transforms (inset)from adjacent areas (i)and (ii)to emphasize the spatial variation in superlattice order parameter.(d)Lattice fringe images in 0.14Li 2TiO 3‚0.86LiMn 0.5Ni 0.5O 2.(e)Lattice fringe images in 0.30Li 2-TiO 3‚0.70LiMn 0.5Ni 0.5O 2.xLi 2M ′O 3‚(1-x)LiMn 0.5Ni 0.5O 2for Li Batteries Chem.Mater.,Vol.16,No.10,20042001。

锰酸锂电池正极材料--锂锰复合氧化物随着电动汽车和可再生能源的需求不断增加，锂离子电池作为一种高能量密度和长循环寿命的新型动力电池，日益受到关注。

在锂离子电池中，正极材料起着储存和释放锂离子的重要作用。

锂锰复合氧化物作为正极材料之一，广泛应用于锰酸锂电池中，具有较高的放电容量和稳定性。

本文将对锂锰复合氧化物进行介绍和分析。

1. 锂锰复合氧化物的结构锂锰复合氧化物的化学式为LiMn2O4，其晶体结构为尖晶石结构。

在这种结构中，锂离子占据八面体空隙，锰离子则分布在正八面体和四面体空隙中。

这种结构稳定且具有较高的离子导电性，能够保证锂离子在充放电过程中的快速迁移。

2. 锂锰复合氧化物的性能锂锰复合氧化物具有较高的比容量和循环寿命。

在0-4.5V范围内，锂锰复合氧化物的比容量可达到300mAh/g以上，而且在循环充放电过程中能够保持较高的容量衰减稳定性。

锂锰复合氧化物还具有较高的热稳定性和安全性，能够满足电池在复杂工况下的使用要求。

3. 锂锰复合氧化物的改性为了进一步提高锂锰复合氧化物的电化学性能，研究人员对其进行了多方面的改性研究。

通过金属掺杂、表面包覆、晶体结构调控等手段，可以降低锂锰复合氧化物在循环充放电过程中的容量衰减速率，提高其电导率和离子扩散系数，从而改善锂离子电池的功率性能和循环寿命。

4. 锂锰复合氧化物在电池中的应用锂锰复合氧化物作为正极材料已被广泛应用于锰酸锂电池中。

由于其丰富的锰资源和低成本，锂锰复合氧化物在电动汽车和储能电站等领域具有较大的市场潜力。

未来，随着电动汽车市场的快速增长和能源存储需求的增加，锂锰复合氧化物作为正极材料的应用前景将更加广阔。

锂锰复合氧化物作为一种重要的锂离子电池正极材料，具有较高的比容量、循环寿命和安全性，且具有较大的市场需求前景。

通过对其结构、性能、改性和应用等方面的深入研究，可以进一步提高其电化学性能，推动锰酸锂电池在新能源领域的发展。

5. 锂锰复合氧化物的挑战和发展趋势尽管锂锰复合氧化物作为正极材料具有诸多优势，但同时也面临着一些挑战。

全面解读尖晶石型高压镍锰酸锂能源学人高压镍锰酸锂正极材料在高能锂离子电池领域的应用极具潜力。

阻碍其规模化应用的主要原因是材料与电解液之间的副反应较为严重。

另外，人们发现减小其颗粒尺寸可以提高倍率性能，但随之而来的是材料的比表面增加又会加剧副反应的进一步发生，因此，需要制备合适粒径的LiNi0.5Mn1.5O4，在保证倍率性能的同时，又能提高电池能量密度和循环寿命。

这也就需要我们对LiNi0.5Mn1.5O4（LNMO）本身的性能有非常清楚的认识。

首先我们来了解一下LNMO的晶体结构。

LNMO以两种多晶型态存在：一种是由Fd3m空间群组成的面心立方相，即无序LNMO（D-LNMO），其中，锰离子和镍离子随机的分布在16d位点处；另外一种是由P4332空间群组成的原始立方相，即有序LNMO（O-LNMO），其中，锰离子和镍离子有序的分布在4a和12d位点处。

其中，D-LNMO有两种形式存在，即氧缺陷LiNi0.5Mn1.5O4-δ和镍缺陷LiNi0.5-xMn1.5-xO4。

锂离子在LNMO中以三维形式迁移，即通过空八面体位点从一个四面体位点转移到附近位点，活化能垒受到过渡金属静电排斥影响巨大。

理论研究表明，O-LNMO中锂离子迁移的活化能低至300meV，与通过第一性原理计算得到的锂离子扩散率值10-8-10-9 cm2/s相一致。

那么如何通过测试表征区分D-LNMO和O-LNMO？有以下三种方法：•XRD分析：D-LNMO的晶格参数（(8.188 Å）稍大于O-LNMO （(8.178 Å），这是因为D-LNMO中有更多的Mn3+存在。

•Raman分析：580-620cm-1区域是八面体中MnO6的Mn-O 伸展模式特征区域。

595cm-1和 612 cm-1两处峰代表的是F2g振动模式。

其中，O-LNMO在此两处的峰强度高于D-LNMO（见图1），这是因为O-LNMO中锰和镍的排布非常有序。

锂离子电池正极材料Li2MnSiO4的合成和电化学性能研究锂离子电池正极材料Li2MnSiO4的合成和电化学性能研究锂离子电池（Li-ion batteries）作为目前最为普遍使用的二次电池，得到了广泛应用。

其中，正极材料的选择对电池性能起着至关重要的作用。

相比于传统的正极材料，锂离子电池正极材料Li2MnSiO4（LMS）因其高能量密度、良好的循环稳定性和较低的成本而备受关注。

本文旨在研究LMS材料的合成方法和电化学性能，以期为锂离子电池的发展提供参考和借鉴。

首先，我们将介绍LMS材料的合成方法。

目前，合成LMS主要采用固相法和溶液法两种方法。

固相法通过高温固相反应将Li2CO3、MnCO3和SiO2进行混合，然后在高温下进行煅烧得到LMS。

溶液法则通过将相应的金属盐溶液混合，并在适当的温度下进行沉淀反应得到LMS。

所述方法各有优劣，但无论采用哪种方法，都需要经过严格的反应条件和多步的合成过程。

接下来，我们将重点讨论LMS材料的电化学性能。

LMS具有高的实际放电容量和很好的倍率性能。

实验结果表明，LMS材料在正常温度下的初始放电容量能够达到200-300mAh/g，且在高倍率5C的放电条件下依然保持较高的容量。

其内部锂离子的扩散和迁移速度较快，有助于提高电池的放电性能。

此外，LMS材料在较长循环寿命测试中也展现出较好的稳定性和循环性能。

然而，LMS材料也存在着一些问题，如容量衰减和电荷传输阻抗增加，这些问题需要进一步的研究和改进。

进一步分析LMS材料的原因可以发现，一方面是由于材料具有较大的体积变化，在充放电过程中会导致电池内部的机械变形和电解液的破裂；另一方面是由于LMS具有较低的电导率，导致电荷传输的困难。

为了解决这些问题，研究者们进行了进一步的优化。

例如，通过合成不同形貌的LMS颗粒（如纳米颗粒、多孔颗粒等），可以增加材料表面积，提高电解液中锂离子的扩散速率，从而提高电池的容量和循环性能。

第49卷第10期 辽 宁化工 Vol .49, No .102020 年 10 月________________________________Liaoning Chemical Industry _____________________________October , 2020二芳醚的合成反应研究概述毕康(温州大学.浙江温州325035 >摘 要：作为普遍的结构，二芳基醚部分存在于多种生物活性天然产物、重要的药物化合物和聚合物中。

二芳基醚在我们的日常生活和实验中都是非常常见的一种化学物质。

它不仅仅可以在农业上 可以作为杀虫剂，而且在日常实验中，它也可以当作配体，给我们的实验带来便捷二芳基醚由于其 在农药研究方面的广泛应用，人们一直在开发其合成的新方法。

之前就有许多相关的方法制备二芳基 醚，包括有过渡金属参与的反应和无过渡金属参与的反应。

目前，人们一直致力于探索更多的方法来获得二芳基醚。

因此，化学家们在开发一条新颖、 关键词：二芳基醚；农药研究；高效 中图分类号：Ty 〇31.2文献标识码：A作为普遍的结构，二芳基醚部分存在于多种生 物法性天然产物，重要的药物化合物和聚合物 中lu 。

其中最明显的例子是万古霉素|21，仅当患者被 革兰氏阳性细菌感染后，在用其他抗生素治疗失败 后才使用。

制备二芳基醚的传统方法是通过Ullmann 型C 一0偶联方法。

但是，该方法通常具有一些缺点，例如化学计量的铜试剂和所需的高温（通常高于 210 T ) t 31。

为了克服这些问题，提出了许多过渡金属催化 的C 一0键偶联反应体系。

主要进展在于铜和钯的 应用。

在不同的配体和金属盐的帮助下，使得其能 够在温和条件下获得的二芳基醚。

然而，对于钯而 言，其缺点例如对产品的污染，高成本，毒性，对 湿气敏感的性质以及结构复杂的难以购买的膦配体 严重限制了其在工业和大规模生产中的应用。

141此 外，回收昂贵的催化剂仍然是一个问题。

锂离子电池正极材料ＬｉＭｎ2Ｏ4的电化学性能锂锰氧化物是目前研究得较多的锂离子正极材料,它主要有ＬｉＭｎＯ2系列和ＬｉＭｎ2Ｏ4系列,其制备方法也较多。

最初的制备方法由Ｈｕｎｔｅｒ提出的,但所得产物的电化学性能差。

为了提高样品的电化学性能,人们提出了多种液相合成法。

如:离子交换法]、固相-液相法、Ｐｅｃｈｉｎｉ法、动态过程法等。

液相合成法反应温度低、时间短,但反应过程复杂,设备要求高,所以目前市场上的锂锰氧化物大多采用固态合成方法。

ＬｉＭｎ2Ｏ4在高温下容量易衰减,即使在室温下性能良好的尖晶石ＬｉＭｎ2Ｏ4,在高温(50℃)下循环50周次后,其比容量将下降20%左右,而在室温或低温(0℃)时循环50周次后,比容量仅下降不到5%。

为了降低高温容量衰减的速度,可采用富锂或富锰的锂锰氧化物,使所用材料在高温下相对稳定。

可适当降低氧活性物质的比表面积,减少电解液在电极表面的分解。

本文采用溶胶-凝胶法合成富锂型Ｌｉ1+ｘＭｎ2Ｏ4,运用循环伏安和恒电流充放电法测量其电化学性能。

所制备的样品放电容量大,可逆性好,并保持原来的两步锂离子脱嵌过程。

1 实验部分1.1 药品和仪器硝酸锂ＬｉＮＯ3(ＡＲ),乙酸锰Ｍｎ(Ａｃ)2•4Ｈ2Ｏ(ＡＲ),柠檬酸Ｃ6Ｈ8Ｏ7•Ｈ2Ｏ(ＣＰ),高氯酸锂ＬｉＣｌＯ4•3Ｈ2Ｏ(ＡＲ),碳酸二甲酯Ｃ3Ｈ6Ｏ3(ＣＰ),碳酸二乙酯Ｃ5Ｈ10Ｏ3(ＣＰ),碳酸乙烯酯Ｃ3Ｈ4Ｏ3(ＣＰ),锂片Ｌｉ(ＡＲ),ＰＶＤＦ(Ｃ2Ｈ2Ｆ2)ｎ(ＡＲ)。

电化学综合测试仪(Ｍｏｄｅｌ283,美国ＰＡＲＣ公司),电池综合测试仪(ＬＫ2000Ｂ,天津Ｌａｎｌｉｋｅ公司),手套箱(Ｕｎｉｌａｂ1200/700Ｗ,德国Ｂｒａｕｎ公司)。

1.2 锂锰氧化物的电化学性能测试文献报道了锂锰氧化物的合成。

将锂锰氧化物、石墨和ＰＶＤＦ按比例85∶10∶5(质量比)混合,用丙酮作溶剂,高速搅拌30～60ｍｉｎ,得到凝胶状物,将此物均匀地涂在铝箔上,在轧机上轧成0.12～0.16ｍｍ的薄膜,然后在120℃下干燥2ｈ,得面积为1ｃｍ2的工作电极。

多晶型MnO_(2)-Ru复合催化剂的制备及其电催化水解析氧性能的研究李佳;袁仲纯;姚梦琴;刘飞;马俊【期刊名称】《人工晶体学报》【年(卷),期】2024(53)2【摘要】在二氧化锰(MnO_(2))中引入杂原子是调整电化学水氧化催化活性位点的有效方法。

在电催化析氧反应(OER)中,虽然已经研究出了许多MnO_(2)的改性方法,但很少有研究以MnO_(2)为主体,讨论MnO_(2)晶型对催化活性的影响。

基于此,本文制备了4种晶型的MnO_(2)(α-MnO_(2)、β-MnO_(2)、γ-MnO_(2)和δ-MnO_(2)),并系统地研究了Ru加入MnO_(2)制备得到的催化剂(x-MnO_(2)-Ru)的OER性能。

线性扫描伏安法和计时电位法测试结果表明,β-MnO_(2)在Ru加入后得到的催化剂(β-MnO_(2)-Ru)电化学性能最佳,在电流密度为10 mA·cm^(-2)时拥有300 mV的较低过电位,而且运行24 h后仍保持较好的催化活性。

结合表征发现,β-MnO_(2)-Ru具有较多的Mn^(3+)和缺陷氧空位,从而具有优异的电催化性能。

【总页数】8页(P336-343)【作者】李佳;袁仲纯;姚梦琴;刘飞;马俊【作者单位】贵州大学化学与化工学院【正文语种】中文【中图分类】TQ032.4【相关文献】1.炭载Ru-Fe催化剂对直接甲酸燃料电池中氧还原的电催化性能研究2.过渡金属掺杂Ru-Se簇合物电催化剂氧还原性能的对比研究3.ZIF-8/C60复合物衍生电催化剂的制备及其水氧化性能4.核壳结构Ru@PtRu纳米花电催化剂的制备及碱性氢析出反应性能研究因版权原因，仅展示原文概要，查看原文内容请购买。

本科学生综合性实验报告学号：200502050240姓名：张绍军专业：化学年级：05 级同组同学：晋文刘万春指导教师及职称：郭俊明（教授）开课学期2008 至2009 学年上学期红河学院理学院锂离子正极材料尖晶石型LiMn2O2的燃烧法制备及电性测试摘要：锂离子电池又称摇椅电池和锂离子二次电池。

它是在20世纪90年代发展起来的电池电源。

尖晶石型Li2Mn2O4 是一种有希望的锂离子正极材料，与目前商业上应用最广泛的锂离子电池正极材料LiCoO2 相比，它具有价格便宜、无毒害、无污染等优点。

尖晶石型Li2Mn2O4 的制备方法也是多种多样的，其基本原理为：使用特定比例的Li盐和Mn盐，在一定条件下与含O氧化剂发生氧化还原反应生成Li2Mn2O4 。

通常使用的方法有固相燃烧法、熔盐燃烧法、液相燃烧法等，使用的原料可以为硝酸盐、醋酸盐、碳酸盐、氧化物、氢氧化物等。

本实验用熔点较低的醋酸锂和醋酸锰以一定摩尔比混合可以直接在熔融状态下燃烧合成尖晶石型Li2Mn2O4 正极材料。

关键词：熔融燃烧合成；尖晶石型；LiMn2O4；锂离子电池2一引言尖晶石型Li2Mn2O4是一种有希望的锂离子正极材料，与目前商业上应用最广泛的锂离子正极材料LiCoO2相比，它具有价格便宜、无毒害、无污染等优点。

尖晶石型Li2Mn2O4的制备方法也是多种多样，其基本原理为：使用特定比例的Li盐和Mn盐，在一定条件下与含O氧化剂发生氧化还原反应生成Li2Mn2O4。

通常使用的方法有固相燃烧法，熔盐然烧法，液相燃烧法等，使用的原料可以为硝酸盐，醋酸盐，碳酸盐，氧化物，氢氧化物等。

熔盐燃烧法也可以用来制备尖晶石型Li2Mn2O4 ，它的反应为固—液—固反应，即固态的原料先在一定的温度下变成熔融的液态，然后通过反应生成固态的产物。

为了得到熔融状态的液态，必须选择熔点较低的原料（如醋酸盐、硝酸盐等）及燃料（如尿素等）。

熔融法一般有两个步骤：第一是熔融体系的形成，需要将原料在电炉（或干燥箱）上低温加热让原料熔化混合；第二是燃烧，将熔融混合的原料在马弗炉上高温加热，让其发生燃烧反应而生成产物。