Anthracite-Based Expanded Graphite as Anode Materials for Sodium-Ion Batteries with Exceptional Sodium Storage Performances

Abstract

High-value materialized clean utilization of coal and anode materials for sodium-ion batteries (SIBs) with large reversible capacity and rapid kinetics are the direction of green and low-carbon economic development. Herein, anthracite-based expanded graphite (AEG) was prepared via a liquid-phase oxidation intercalation-rapid thermal reduction method by employing homemade anthracite-based graphite (AG) as anode materials for SIBs. The unique morphological structure of AEG provides superior structural stability and sodium storage behavior dominated by capacitive adsorption, which enhanced reaction kinetics, at the time of intercalation/decalcification of Na+. Consequently, the AEG electrodes demonstrated a high initial reversible specific capacity of 326 mA h g-1 at 30 mA g-1 and still maintained a specific capacity of 88 mA h g-1 at a high rate of 10 A g-1 when deployed in SIBs. Furthermore, the as-prepared sample presented excellent cycling stability, maintaining a specific capacity of 152 mA h g-1 after 1,000 cycles at a rate of 1 A g-1, with a capacity retention rate of 85%. This work presents a broad and promising potential for the greening of energy sources and environmental protection.

Keywords: coal, expanded graphite, Sodium-ion batteries, rapid kinetics, capacitive adsorption