Regulation voltage of LiNiPO4 by density functional theory (DFT) calculation to move towards practical application

Abstract

AbstractLiNiPO4 (working at ~5.1 V) shows potential advantages in the competition of cathode materials for lithium‐ion batteries (LIBs) because of high energy density. However, the high‐voltage electrolyte developed can only remain relatively stable in the range of less than 4.8 V, so the operating voltage of LiNiPO4 needs to be adjusted to smaller to better exploit its high‐voltage advantages. To regulate the operating voltage of LiNiPO4 while ensuring the relative stability of its electrochemical properties, in this work, all the 3d, 4d, and 5d transition metals (TMs) are, respectively, doped into the Ni site of LiNiPO4 to screen out the doped models with excellent electrochemical performance. In particular, the changes in lattice structure, electronic properties, formation energy, mechanical properties, anisotropy, and working voltage were used as screening criteria. By considering the above screening criteria, the Cr‐ and Fe‐doped LiNiPO4 with open circuit voltage ~4.7 and ~4.8 V are considered to have leading performance and can be used for applicable high‐voltage LIBs. The screening results of this work can provide an overall understanding of the doping of LiNiPO4 by TMs and have advanced a theoretical idea for the design of new high‐voltage LIBs cathode materials.