The improved physical and electrochemical performance of LiNi0.35Co0.3−xCrxMn0.35O2 cathode materials by the Cr doping for lithium ion batteries

We have successfully prepared the layered structure LiNi0.35Co0.3−xCrxMn0.35O2 with various Cr contents by a co-precipitation method. Many measurement methods have been applied to characterize the physical and electrochemical properties of LiNi0.35Co0.3−xCrxMn0.35O2, such as XRD, SEM, BET and electrochemical test. SEM showed that the addition of Cr has obviously changed the morphologies of their particles and increased the size of grains. The specific surface area of LiNi0.35Co0.3−xCrxMn0.35O2 decreases lineally from 4.9 m2 g−1 (x = 0) to 1.8 m2 g−1 (x = 0.1) with the increasing of Cr contents. Moreover, we have found that the Cr doping can greatly improve the density of the powder, which is beneficial to solve the problem of lower electrode density for these layered LiNi0.35Co0.3−xCrxMn0.35O2 cathode materials. Electrochemical test indicated that the cycling performance of LiNi0.35Co0.3−xCrxMn0.35O2 can be significantly improved with the increasing of Cr contents, although the initial discharge capacity of the sample has a little decrease.