The role of PrPO4 in improving the electrochemical performance of cobalt-free Lithium-rich oxide cathode

Abstract

The utilization of lithium-rich layered oxides (LLOs) materials shows promising possibilities for the innovation of high-capacity Li-ion batteries with enhanced energy density. However, their practical applications are limited by continuous voltage decay, inferior cycling stability, and poor rate capability. In this work, a novel doping strategy is proposed, where PrPO4 is introduced during the high-temperature solid-state reaction to prepare Co-free Li-rich layered oxides. It is found that other than as a dopant, PrPO4 can activate Li2MnO3 to form well-distributed Pr0.96Mn0.982O3 and Li3PO4 in LLOs particles, which availably suppresses the phase transition. The obtained material increases the initial coulombic efficiency (ICE) from 75.8% to 84.1%, and improves capacity retention from 74.6% to 90.9% compared with the pristine material. Meanwhile, the average voltage decay decreases from 2.33 mV/cycle to 1.25 mV/cycle over 200 cycles. This work provides valuable insights into the development of LLOs using rare-earth phosphate, offering valuable knowledge for further advancements in this field.