Self-Propagating Fabrication of a 3D Graphite@rGO Film Anode for High-performance Potassium-Ion Batteries

Graphite, with abundant resources and low cost, is regarded as a promising anode material for potassium-ion batteries (PIBs). However, because of the large size of potassium ions, the intercalation/deintercalation of potassium between the interlayers of graphite results in its huge volume expansion, leading to poor cycling stability and rate performance. Herein, a self-propagating reduction strategy is adopted to fabricate a flexible, self-supporting 3D porous graphite@reduced graphene oxide (3D-G@rGO) composite film for PIBs. The 3D porous network can not only effectively mitigate the volume expansion in graphite but also provide numerous active sites for potassium storage as well as allow for electrolyte penetration and rapid ion migration. Therefore, compared to the pristine graphite anode, the flexible 3D-G@rGO film electrode exhibits greatly improved K-storage performance with a reversible capacity of 452.8 mAh g