Fine-Tuned Synthesis for Reducing Residual Lithium in Ni-Rich Cathode Materials for Lithium-Ion Batteries

초록

Incidentally generated residual lithium on the surfaceduring thesynthesis of Ni-rich cathode materials for lithium-ion batteries hasbeen considered one of the most serious problems to be solved. Inthis work, a suitable condition for simple washing and post-heat treatmentwith additional lithium salt process for preparing LiNi0.8Co0.1Mn0.1O2 is optimized througha systematic evaluation. By varying amount of additional lithium salt,the most appropriate input is found to be 5 wt % in terms of electrochemicalperformance, such as initial capacity, capacity retention, and ratecapability. In addition, it is verified by several techniques thatit has the ideal composition (lithium/transition metal = 1:1) andthe stable structure of R3 ̅m. From electrochemical impedance spectroscopy, it is found that thegood performance of the cell assembled using the optimized materialis originated from lowering resistance between the cathode and theelectrolyte.

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