Coupling graphene microribbons with carbon nanofibers: New carbon hybrids for high-performing lithium and potassium-ion batteries

Carbon‑carbon allotropic hybrids exhibit remarkable properties, including exceptional electrochemical charge storage capacities. A novel hybrid material composed of 1D carbon nanofibers (CNF) and 2D graphene micro-ribbons (GMR) was synthesized and incorporated as anodes in Li-ion batteries (LIB) and Potassium-ion batteries (KIB) for improved storage capacity. CNF-GMR material was hybridized simultaneously by one-step chemical vapour deposition (CVD) synthetic process, wherein the CNF were grown on the graphene surface using an iron oxide catalyst. Meanwhile, the GMRs were formed by the catalytic cutting of few-layer graphene. This unique carbon‑carbon allotropic hybrid exhibits excellent structural integrity, good electrical conductivity (718 S/m) and high specific surface area (305.6 g/m²). The as-prepared materials, when used as an anode in batteries, exhibited a highly reversible capacity (598 mAhg⁻¹ and 410 mAhg⁻¹ at 0.10 Ag⁻¹ for LIB and KIB, respectively) with fast charging and discharging capability, and long-term cycling stability with 99% Coulombic efficiency over 1000 cycles.