摘要
为了提高磷酸铁锂(LiFePO_4)电池在宽温度范围内的性能,研究LiBF_4-LiBOB复合盐和LiTFSI-LiBOB复合盐用于替代LiPF_6作为非水电解质的锂盐。分别通过恒流充放电测试、循环伏安测试和热重分析法研究使用LiPF_6,LiBF_4-LiBOB和LiTFSI-LiBOB作为锂盐的LiFePO_4/Li半电池的性能。结果显示:LiBF_4-LiBOB和LiTFSI-LiBOB复合盐的热稳定性高于LiPF_6;在LiTFSI基电解液中添加LiBOB可以提高铝箔的抗腐蚀性;使用LiBF_4-LiBOB和LiTFSI-LiBOB复合盐的电池电化学性能相对于使用LiPF_6的电池有明显改善。因此LiBF_4-LiBOB和LiTFSI-LiBOB复合盐电解液可以用来改善锂电池宽温度范围下的性能。
To achieve good performance for LiFePO4-based batteries operated at a wide temperature range,mixed salts of LiBF4 LiBOB（lithium bis（oxalato）borate） and LiTFSI（lithium bis（trifluoromethanesulfonyl）imide）-LiBOB were investigated as alternative lithium salts to LiPF6 in non-aqueous electrolytes.LiFePO4/Li half cells using LiPF6,LiBF4-LiBOB and LiTFSI-LiBOB slats as lithium salts were investigated by galvanostatic cycling,cyclic voltammetry,thermogravimetric analysis.The results show that LiBF4-LiBOB and LiTFSI-LiBOB mixed salts are much more thermally stable than LiPF6.Corrosion of Al foil in the LiTFSI-based electrolytes can be suppressed successfully by the addition of LiBOB as a co-salt.The electrochemical performance of LiBF4-LiBOB and LiTFSI-LiBOB mixed salts based cells are both better than that of LiPF6-based cell.LiTFSI-LiBOB mixed salt based electrolyte is considered to be a very promising electrolyte candidate for Li-ion batteries that will be used in wide-temperature applications.
基金
Project(2013JSJJ027)supported by the Teacher Research Fund of Central South University,China
