掺杂NCA工艺对锂离子电池正极性能的影响

Effect of doping NCA process on cathode performance of lithium-ion battery

锂离子电池正极材料的界面及结构稳定性对其性能发挥具有重要作用,因此,通过掺杂等表面处理方法对其进行改善成为当前研究热点。通过高价离子的掺杂改善镍钴铝酸锂(LiNi_(0.8)Co_(0.15)Al_(0.15)O_(2)(NCA))正极材料表面形貌、晶体强度及电极过程动力学,进而稳定提升NCA电化学性能;并通过改变掺杂工艺探讨了烧结时间、烧结温度、掺杂离子种类对其结构、形貌及性能等方面的影响。研究发现:Mo、Ti、Nb等3种掺杂离子均能成功地掺杂进NCA材料里,在800℃烧结12 h的情况下,以Ti为掺杂离子,可拥有较好的充放电性能,其首次放电比容量可达到153 mA·h/g;以Nb为掺杂离子所制得的正极材料在1C循环性能测试中性能较好,且R_(SEI)最小;以Mo为掺杂离子的R_(ct)较大,电化学活性较好。

The interface and structural stability of lithium-ion battery cathode materials play an important role in their performance,so the improvement of surface treatment methods such as doping has become a hot research topic.In this paper,the surface morphology,crystal strength and electrode process dynamics of NCA cathode materials were improved by doping high-valence elements,and the electrochemical performance of NCA was stably improved.The influence of doping process(sintering time,sintering temperature,and doping element types)on the structure morphology and performance was discussed.The results show that Mo,Ti and Nb can be successfully doped into NCA materials.Under the condition of 800℃for 12 hours,Ti doped element can have good charge-discharge performance,and its initial discharge specific capacity can reach 153 mA·h/g.The cathode material prepared with Nb as doping element has good performance and minimum R_(SEI) in 1C cycle performance test.The R_(ct) with Mo as doping element is larger and the electrochemical activity is better.