Generality Rules and Synergistic Effect of Mitigating the Jahn–Teller Effect by Multisites Compositionally Complex Doping

The Jahn-Teller (JT) deformation triggers severe structural distortion and large capacity fading in the cathode materials of alkali-ion batteries. Although conventional doping containing over 20 dopant species has been demonstrated to suppress the JT effect, how the short-range and cooperative JT effect are regulated remains an open question. Recently, the new compositionally complex (high entropy) doping has been validated in various oxide cathodes and achieved "zero strain", but the reported "synergistic effect" is largely factual reporting with a limited fundamental understanding of the link between multicomponents and the JT effect. By comparing a group of spinel LiMn