Intralayer ordered structure engineering for long-life Mn-based potassium-ion battery cathodes

Mn-based layered oxides have become one of the most promising cathode materials in potassium -ion batteries (PIBs) due to their high theoretical specific capacity. Nonetheless, the Jahn -Teller effect of Mn 3 + leads to lattice distortion and a high K + migration barrier, resulting in structural instability during the charge/discharge processes. To effectively overcome these problems, this work provides a method to change electronic energy levels to suppress the Jahn -Teller effect through the synergistic regulation of multiple specific element doping. The Xray diffraction pattern of K 0.4 Mn 0.7 Ti 0.1 Ni 0.1 Cu 0.1 O 2 shows its P3 -type structure. The electrochemical test results demonstrate that K 0.4 Mn 0.7 Ti 0.1 Ni 0.1 Cu 0.1 O 2 exhibits superior rate capacity, higher discharge specific capacity, and significant cycling stability (with a capacity retention rate of 80 % after 860 charge/discharge cycles). The in -situ X-ray diffraction pattern demonstrates the high reversibility of the electrochemical process of K + insertion/extraction. First -principles calculations have confirmed that the electronic energy levels of K 0.4 Mn 0.7 Ti 0.1- Ni 0.1 Cu 0.1 O 2 have better dispersion, the K + migration channel has been effectively optimized, and the K + migration barrier has been reduced. This study provides a significant and effective reference for the design of advanced PIBs with high performance.