First-Principles Study: Tuning the Redox Behavior of Lithium-Rich Layered Oxides by Chlorine Doping

Lithium-rich layered oxides (LLOs) are promising cathode materials for next-generation lithium ion batteries with high energy density. However, the charge cutoff potential of 4.8 V constrains seriously the actual application of LLOs. Herein, using density functional theory (DFT) calculation, we investigated the tuning mechanism of chlorine doping on the redox potential and redox process in LLOs. The results showed that chlorine doping can decrease the charge potential, modulate the ratio of two redox couples of cation and anion, and lower the band gap of LLOs. These tunings were beneficial for the modification of the safety, cycling stability, and voltage decay of LLOs materials. This work opens up a new route in terms of performance improvement via tuning of redox behavior based on deep understanding of anion doping mechanism.