二氟草酸硼酸锂的制备与性能研究

Study on preparation and properties of lithium-difluoro(oxalato) borate

以无水氯化铝为催化剂,以四氟硼酸锂和无水草酸为原料,制备高纯二氟草酸硼酸锂(Li ODFB)。研究了反应时间、反应温度和反应物配比(四氟硼酸锂与草酸物质的量比)对产品纯度的影响以及结晶温度和结晶时间对产品收率的影响。实验结果表明,在反应温度为10℃、反应时间为4 h、反应物配比为1∶1、结晶温度为-20℃、结晶时间为4 h条件下,制得Li ODFB的纯度可达99.97%、收率可达95.9%。另外,以Li ODFB作为电解液添加剂,可以有效改善锂电池的高温、常温和低温性能。

Lithium-difluoro(oxalato)borate(LiODFB)with high purity was synthesized by the raw materials of lithium tetra-fluoroborate and anhydrous oxalic acid,with anhydrous aluminum chloride as the catalyst.The influences of reaction time,re-action temperature,and the amount-of-substance ratio of lithium tetrafluoroborate to anhydrous oxalic acid on the purity of product and the influences of crystallization temperature and crystallization time on the yield of product were investigated.The best conditions were described as follows:the reaction temperature was 10℃,the reaction time was 4 h,the amount-of-sub-stance ratio of the reaction materials was 1∶1,the crystallization temperature was-20℃and the crystallization time was 4 h.Under the best conditions,the purity of LiODFB was 99.97%and the yield was 95.9%.In addition,adding LiODFB in electrolyte could effectively improve the performance of battery at high temperature,room temperature and low temperature.