不同Mn源对Li_(1+x)Mn_(2-x)O_4尖晶石正极材料的电化学性能的影响

Effects of Different Mn Sources on the Electrochemical Performances of Li_(1+x) Mn_(2-x)O_4 Spinel Cathode Materials

以 Li2 CO3为 Mn源 ,采用醇水混合溶剂分散与中温固相反应法考察了 Mn(NO3) 2 · 6H2 O,Mn(Me CO2 ) 2· 4 H2 O,Mn CO3,化学 Mn O2 (CMD)和电解 Mn O2 (EMD)等不同 Mn前驱物对制备 Li1 + x Mn2 - x O4尖晶石正极材料的电化学性能的影响 ,并采用 XRD,BET,TEM等手段对材料进行了表征。结果表明 ,由不同 Mn前驱物制备的正极材料均呈尖晶石结构 ,其容量大小和循环性能 (依 Mn源为顺序 )为 EMD>Mn(NO3) 2 · 6H2 O>Mn CO3>Mn(Me CO2 ) 2 · 4 H2 O>CMD。材料呈立方晶体 ,比表面积 (依 Mn源为顺序 )为 CMD>Mn CO3>Mn(NO3) 2 · 6H2 O>Mn(Me CO2 ) 2 · 4 H2 O>EMD,正好与容量及稳定性顺序相反。采用本文的制备方法时 ,EMD和 Mn(NO3) 2 · 6H2 O都是较好的 Mn前驱物 ,Mn(Me CO2 ) 2 · 4 H2 O和 Mn CO3也可以做 Mn源 ,但焙烧时需要富氧气氛 ,CMD不适宜作

The spinel cathode materials Li 1+x Mn 2 x O 4 were prepared by dispersion with ethanol-water mixed solvent and solid state reaction at moderate temperature using Li 2CO 3 as Li precursor and Mn(NO 3) 2·6H 2O, Mn(MeCO 2) 2·4H 2O,MnCO 3,chemical MnO 2(CMD) and electrolytic MnO 2(EMD) as Mn sources respectively. The effects of different Mn sources on the electrochemical performances of Li 1+x Mn 2 x O 4 spinel cathode materials were investigated, and characterizations were carried out by XRD,BET and TEM. The results displayed that the cathode materials prepared using different Mn sources are spinel structure, their capacity and cyclic performance is as EMD>Mn(NO 3) 2·6H 2O>MnCO 3>Mn(MeCO 2) 2·4H 2O>CMD. The cathode materials are cubic crystals , their specific surface areas are CMD>MnCO 3>Mn(NO 3) 2·6H 2O>Mn(MeCO 2) 2·4H 2O>EMD. EMD and Mn(NO 3) 2·6H 2O are better Mn sources if solid state reactions are used to prepare the cathode materials . Whereas Mn(MeCO 2) 2·4H 2O and MnCO 3 can also be used as Mn sources if solid state reactions are used to prepare the cathode materials, but the oxygen rich atmosphere of calcination is necessary. CMD is not suitable for Mn precursor.