ABSTRACT Layered transition metal oxides represent attractive cathode candidates for potassium‐ion batteries (PIBs), due to their high theoretical specific capacity. However, sluggish K + diffusion and structural instability, stemming from the inherent K + /vacancy ordered structure, lead to poor rate performance and cycling stability. Herein, a charge‐ion coupling engineering strategy, wherein transition‐metal electronic structure is tuned to modulate interlayer K + /vacancy configurations, is initially pioneered. Specifically, a K + /vacancy‐disordered P3‐type structure is constructed via targeted transition metal (TM) doping in Mn/Co‐based layered oxides. Exploiting the identical valence of Ti 4+ and Mn 4+ coupled with their divergent redox potential, the doping sites suppress charge ordering within TM slabs through modulating charge delocalization, thereby inducing interlayer K + /vacancy disordering. The K + /vacancy disordered K 0.5 Mn 0.8 Co 0.1 Ti 0.1 O 2 delivers long‐term stability with 58.6 mAh g −1 over 800 cycles at 1 A g −1 and remarkable rate capability of 61.7 mAh g −1 at 2 A g −1 , facilitating a highly reversible single‐phase solid‐solution reaction in K 0.5 Mn 0.8 Co 0.1 Ti 0.1 O 2 and enhancing the structural stability during K + extraction/insertion. Meanwhile, molecular dynamics simulations demonstrate that the K + /vacancy disordered structure contains interconnected channels enabling continuous and rapid K + diffusion. This work establishes a cation substitution strategy for manipulating K + /vacancy order‐disorder to develop high‐performance, kinetically robust cathode materials for next‐generation PIBs.
Jia et al. (Sun,) studied this question.