Synergistic Kinetics Modulation at Graphite Interface Enables Ultrafast and Durable Potassium‐Ion Batteries

Abstract

Abstract Graphite has been considered as the most promising anode material for potassium‐ion batteries (PIBs) commercialization due to its high theoretical specific capacity and favorable charge‐discharge platform. Nevertheless, in conventional KPF 6 ‐based electrolytes, the practical implementation is hindered by sluggish potassium‐ion (K + ) transport through solid electrolyte interphase (SEI), leading to poor rate capability and inferior cycling durability. A nanostructured SiO 2 modification layer is constructed on a graphite surface (SiO 2 ‐Graphite) to regulate the interfacial kinetics, which can enable a faster K + diffusion capability and lower K + migration barrier. Notably, the SiO 2 ‐Graphite anode exhibits high initial Coulombic efficiency (84.1%), excellent cycling stability (400 cycles with a capacity retention of 71%), and high‐rate capability (213 mAh g −1 at a high current density of 500 mA g −1 ) in conventional KPF 6 ‐based electrolyte. In addition, the PB||SiO 2 ‐Graphite full cell also demonstrates good cycling stability (90% capacity retention after 600 cycles) and excellent rate performance (high specific capacity at a current density of 2000 mA g −1 ), which outperforms that of most previously reported PIBs systems. This interfacial kinetics regulation strategy provides new insights into improving the cycling stability and rate capability of electrodes.