In Situ Catalytic Formation of Graphite-Like Carbons with Superior Potassium Storage Performance

Abstract

Commercialized graphite is a candidate for the anode material of K-ion batteries (KIBs), as it can form stable intercalation compounds with potassium. However, its narrow interplanar spacing hinders the rapid extraction/insertion of large-sized potassium ions, resulting in poor rate capability and inferior cycling stability. Herein, graphite-like carbons (GLCs) are formed via combining in situ catalysis with plasma sintering of biomass carbon. The coexistence and intergrowth of ordered graphitic layers and the disordered carbon provide abundant functional groups, suitable pore size distribution, and wide carbon interlayer spacing. Thus, GLC anodes display high charge capacity and outstanding stability for KIBs. Moreover, the ʻadsorption-intercalationʼ mechanism of K-ion storage in the GLC is clarified by in-situ X-ray diffraction (XRD) and ex-situ transmission electron microscopy (TEM) tests. This work offers a new synthesis strategy for the GLC and guidance for the design of high-performance carbon anode materials.

Keywords: K-ion batteries, Anode, Graphite-like carbon, Storage mechanism, Capacity