CAJ | 학술논문

用真空固相反应与液相还原结合的方法,合成了锂离子电池正极材料--金属银掺杂的覆碳磷酸铁锂(LiFePO_4/Ag/C),用X射线衍射、扫描电镜、循环伏安、交流阻抗等技术研究其结构、形貌及电化学性能.结果表明,该正极材料为橄榄石型晶体、类球形颗粒(粒径范围约为0.5～2.0μm);Ag掺杂能使合成的LiFePO_4颗粒粒径更小、分布更均匀,有效地提高其电化学循环性能;LiFePO_4/Ag/C电极0.1C倍率充放的首次放电比容量为138.2mAh/g,50次循环的放电比容量为130.1mAh/g,最高放电比容量为148.3mAh/g;LiFePO_4/Ag/C正极材料具有良好的锂离子传导性能,其锂离子扩散系数(D_(Li)~+)为8.94×10~(-15)cm~2/s.
용진공고상반응여액상환원결합적방법,합성료리리자전지정겁재료--금속은참잡적복탄린산철리(LiFePO_4/Ag/C),용X사선연사、소묘전경、순배복안、교류조항등기술연구기결구、형모급전화학성능.결과표명,해정겁재료위감람석형정체、류구형과립(립경범위약위0.5～2.0μm);Ag참잡능사합성적LiFePO_4과립립경경소、분포경균균,유효지제고기전화학순배성능;LiFePO_4/Ag/C전겁0.1C배솔충방적수차방전비용량위138.2mAh/g,50차순배적방전비용량위130.1mAh/g,최고방전비용량위148.3mAh/g;LiFePO_4/Ag/C정겁재료구유량호적리리자전도성능,기리리자확산계수(D_(Li)~+)위8.94×10~(-15)cm~2/s.
Silver-doped and C-coated lithium-iron-phosphate samples,LiFePO_4/Ag/C,were synthesized by solid-state reaction under vacuum condition combining the solution methods.The physical properties and electrochemical performances of as-synthesized samples were investigated by X-ray diffraction,SEM,the cyclic voltammetry and the electrochemical impedance spectroscopy(EIS).The results indicated that the samples showed the olivine structure and semi-spherical particle with narrow distributed particle size ranging between 0.5 and 2.0μm;and the particle size was uniformed and the electrochemical properties were improved by Ag doping obviously.The discharge capacities of the initial and 50~(th) cycles of the sample electrode were 138.2 and 130.1mAh/g respectively and the highest discharge capacity of the electrode was 148.3mAh/g.Diffusion coefficient of lithium ion D_(Li)~+ of LiFePO_4/Ag/C calculated by EIS testing was 8.94×10~(-15)cm~2/s.