Filling carbon: a microstructure-engineered hard carbon for efficient alkali metal ion storage

Abstract

Carbonaceous materials are the most promising anodes for alkali metal-ion batteries (AMIBs); however, it is still a great challenge to construct carbonaceous materials with elaborate microstructures to achieve superior electrochemical performance. Herein, a space-confined chemical vapor deposition (SC-CVD) method is developed for the first time to fill graphitic-like carbon domains into the micropores of commercial activated carbon (AC) to form hard carbon materials with tunable microstructures. The interlayer spacing of graphitic carbon, the size of graphitic carbon domains, and the micropores of the filling carbon (FC) materials can be facilely adjusted by changing the SC-CVD residence time and the adoption of post-heat treatment. The as-prepared FC demonstrates an excellent sodium storage capacity of 435.5 mA h g⁻¹ at 20 mA g⁻¹ and excellent cycling stability with a capacity retention of 80% over 1000 cycles. Besides, the FC also delivers outstanding electrochemical performance for lithium- and potassium-ion batteries. Impressively, record-level potassium storage performance is achieved by the FC. Moreover, the effect of carbon substrates and carbon sources on the microstructures and electrochemical properties of as-obtained FC is systematically investigated. This work provides a practical strategy to engineer commercial carbon materials to construct advanced hard carbon materials for high-performance AMIBs.