Thermal Reductive Perforation of Graphene Cathode for High-Performance Aluminum-Ion Batteries

Controlling the structure of graphene-based materials with improved ion intercalation and diffusivity is crucial for their applications, such as in aluminum-ion batteries (AIBs). Due to the large size of AlCl₄⁻ ions, graphene-based cathodes have specific capacities of ≈60 to 148 mAh g⁻¹, limiting the development of AIBs. A thermal reductive perforation (TRP) strategy is presented, which converts three-layer graphene nanosheets to surface-perforated graphene materials under mild temperature (400 °C). The thermal decomposition of block copolymers used in the TRP process generates active radicals to deplete oxygen and create graphene fragments. The resultant material has a three-layer feature, in-plane nanopores, >50% expanded interlayer spacing, and a low oxygen content comparable to graphene annealed at a high temperature of ≈3000 °C. When applied as an AIB cathode, it delivers a reversible capacity of 197 mAh g⁻¹ at a current density of 2 A g⁻¹ and reaches 92.5% of the theoretical capacity predicted by density-functional theory simulations.