Edge-enriched and S-doped carbon nanorods to accelerate electrochemical kinetics of sodium/potassium storage

Hard carbon is regarded as a promising anode material for sodium/potassium-ion batteries, which have attracted much attention in grid-scale energy storage. However, it still suffers from the sluggish electrochemical kinetics rooted in the turbostratic structure of carbon, leading to an inferior rate capacity. Herein we utilize a facile strategy to fabricate the edge-enriched and S-doped carbon nanorods (SCNs) with controllable diameter and highly-oriented carbon layer arrangement. The abundant edges lead to the shorter diffusion path of ions, as well as the enlarged layer spacing, both contribute to the rapid kinetics of ionic insertion/desertion. Such a unique highly-oriented structure enables the SCNs anodes to deliver excellent rate capacities and long-lasting cycling life for both sodium and potassium ion storage. The density functional theory (DFT) results demonstrate the enhanced adsorption and reduced ions diffusion energy barrier of Na+ ions near the S-doped active sites, which substantiates the promoted electrochemical kinetics of SCNs electrodes. This work inspires more ideas for rational design of advanced electrodes and provides an in-depth insight into the reaction kinetics of carbonaceous anodes.