Heteroatom-driven the rapid electrochemical process of anthracite derivatives in sodium-ion battery

Abstract

Anthracite exhibits great potential for anodes in sodium-ion batteries (SIBs) attributed to its rich reserve and high carbon content. Here, a high-performance anthracite-derived carbon with both N and Cl doping (ACp-N-Cl) was prepared by a low-temperature pyrolysis process, which showed a large reversible capacity and enhanced rate capability for SIBs. Calcining the purified anthracite and ammonium chloride in an inert atmosphere at 400 °C resulted in a porous carbon engineered with numerous edge defects and topological irregularities, which were beneficial to the storage of Na⁺ by lowering the ion migration energy barrier. The obtained ACp-N-Cl electrode materials exhibited outstanding electrochemical performances in both rate capability and long-term stability, delivering a discharge capacity of 220 mAh g^-1 (@0.02 A g^-1) after 50 cycles and retaining a capacity of 173 mAh g^-1 after 8000 cycles at 1 A g^-1. Kinetic analysis confirmed that the performance enhancement was primarily attributed to the increased pseudocapacitive contribution and improved ion transport by N and Cl heteroatoms doping. This study offers a promising method to produce carbon anodes from low-cost coal-based precursors, which is practicable for a large-scale production.

Keywords

Anthracite / carbon anode / sodium-ion battery / heteroatoms; doping

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