Boron-doped polyhedral graphite catalyzed by h-BN via structural induction for lithium storage

Abstract

Artificial graphite is extensively used in power lithium-ion batteries for its exceptional stability and high-rate performance. However, the commercial high-temperature graphitization process is conducted at temperatures up to 3000 °C to enhance the degree of graphitization, resulting in significant electricity consumption and lengthy production cycles. This study aimed to lower graphitization temperatures and shorten times by using h-BN as a catalyst. Employing anthracite coal as the precursor and catalyzing with BN at 2800 °C for just 2 h, we achieved a remarkable graphitization degree of 93.3 %, compared to 83.5 % without BN. This indicates BN's effectiveness in accelerating graphite phase formation. Interestingly, the resultant graphite exhibited polyhedral morphology and incorporated boron doping. As edges increased, lithium-ion diffusion pathways and boron doping enhanced stability within the graphite layers, imparting high rate capability and robust cycle performance. The material delivered reversible specific capacities of 369.6 and 226 mA h g−1 at current densities of 0.1 and 3C, and maintained capacity retentions of 95 % and 92 % after 500 cycles at 0.5C and 1C. These results substantiate the potential for large-scale production of artificial graphite from anthracite coal using BN catalysis and underscore its promise as a superior anode material for lithium-ion batteries.