热电池用锂钒氧化物正极材料的放电模式

来源期刊:中国有色金属学报2008年第1期

论文作者:李志友 曹笃盟 周科朝

文章页码:59 - 66

关键词:钒氧化物;锂钒氧化物;正极;热电池

Key words:vanadium oxide; lithium vanadium oxide; cathode; thermal battery

摘    要:合成V2O5-V2O3-Li2O体系的3种化合物LiV3O8、γ-LiV2O5和VO2,并以其作为热电池正极活性物质、锂硼合金为负极、LiCl-KCl为电解质进行500 ℃、100 mA/cm2的放电实验,研究该正极活性物质在放电中的物相转变过程,同时对V2O5、β-Li0.3V2O5、VnO2n+1和VnO2n+1的放电反应进行分析。结果表明,LiV3O8、γ-LiV2O5和VO2均进行分解式放电反应,生成LiV2O5、Li3VO4、V2O3和LiVO2等物相。分析认为V2O5和β-Li0.3V2O5可能出现嵌入反应直至转变为γ-LiV2O5,再由γ-LiV2O5进行放电,VnO2n+1和VnO2n+1放电最终也将生成Li3VO4和V2O3。γ-LiV2O5和VO2放电过程中V4+歧化反应产生Li3VO4相和V2O3相,Li3VO4相较差的电子导电性使正极材料失去快速放电能力。

Abstract: Thermal battery potential cathode materials, LiV3O8, γ-LiV2O5 and VO2, were synthesized and discharged at a current density of 100 mA/cm2, with an anode of Li-B alloy and electrolyte of LiCl-KCl eutectic molten salt at 500 ℃. The attention was paid to the phase evolutions to investigate the discharge characteristics of these cathode compounds in the V2O5-V2O3-Li2O system at high temperature. The discharge reactions of V2O5, β-Li0.3V2O5, VnO2n+1 and VnO2n-1 were also discussed. The results indicate that LiV3O8, γ-LiV2O5 and VO2 all show decomposing discharge mechanism in which LiV2O5, Li3VO4, V2O3 and LiVO2 gradually appear. The phase relationship is schemed for the V2O5-V2O3-Li2O system to be discharged as thermal battery cathode, during which V2O5 and β-Li0.3V2O5 may firstly turn to dischargeable γ-LiV2O5 through the lithium-insertion reaction, VnO2n+1 and VnO2n?1 are both discharged to become the mixture of Li3VO4 and V2O3 finally. Because of the disproportionate reaction of V4+ in γ-LiV2O5 and VO2 on discharging, Li3VO4 and V2O3 are obtained. The low electron-conductivity of Li<>3VO4 may make these cathode materials all lose the discharge ability at high current density needed for thermal battery.

基金信息:国家自然科学基金资助项目

有色金属在线官网  |   会议  |   在线投稿  |   购买纸书  |   科技图书馆

中南大学出版社 主办 版权声明   电话:0731-88830515 88830516   传真:0731-88710482   Email:administrator@cnnmol.com

互联网出版许可证:(署)网出证(湘)字第028号   湘ICP备09001153号