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

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 KPF₆-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 SiO₂ modification layer is constructed on a graphite surface (SiO₂-Graphite) to regulate the interfacial kinetics, which can enable a faster K⁺ diffusion capability and lower K⁺ migration barrier. Notably, the SiO₂-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 KPF₆-based electrolyte. In addition, the PB||SiO₂-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.