Structure change during charging processes of LiMyNi1-yO2 (M = Ca, In, Nb) as the cathode active material for lithium secondary batteries

Abstract

In order to improve the cycleability of LiNiO2 as the cathode active material for lithium secondary batteries, impurity-containing LiNiO2s (LiMyNi1-y,O2, M = Ca, In, Nb) were prepared. By changing the content of y, the largest capacity was obtained at y = 0.005. The charge-discharge cycleability of Ca - or Nb-containing LiNiO2 was improved by about 8-10% for 40 cycles. By measuring the diffusion coefficient of Li+ in the cathode and the in situ XRD change in the charging process, it was found that the structure change of the cathode during the charging process was suppressed by exchanging a part of Ni with Ca or Nb.