Novel Graphitic Sheets with Ultralong Cycling, Ultrafast Rate, and High Capacity for Sodium Storage

Achieving fast energy storage at high power levels from sodium-ion batteries (SIBs) is essential for terawatt-hour (TWh) supply/storage. Designing and preparing electrode materials to meet ultrafast rates is a necessity. Herein, we design and synthesize a graphitic sheet (GS) anode material with abundant structural defects and mesopores by a low-temperature, simple, and short-flow method using calcium carbide (CaC₂) and CCl₄ feedstocks. The GSs are of 20–130 nm in thickness and several micrometers in width, which support a fast charge transfer rate for [Na-diglyme]⁺ and a high storage capacity. After annealing, the treated GSsH500 exhibits a fast rate performance (23 s), a long cycle stability (40 000 cycles), and a high Coulomb efficiency (99.95%) by pseudocapacitive process. These findings provide new highlights for designing high-capacity, long-life graphite anode materials of SIBs for grid-scale energy storage.