Nitrogen‐doped porous biomass carbon with ultrastable performance as anodes for potassium‐ion batteries

Abstract

Abstract The potential safety hazards and limited lithium resources of lithium‐ion batteries (LIBs) have restricted their practical application. Potassium‐ion batteries (KIBs) are a novel energy storage technology with great cost advantages and are a promising alternative to LIBs. However, because of the large ionic radius of K+, the common anode materials used in LIBs exhibit a large volumetric expansion and structural collapse in the process of charging and discharging in a KIB. In this work, the prepared nitrogen‐doped porous carbon fibers (P‐CFs) from bombyx mori silk cocoons via a simple KCl activation and high‐temperature carbonization method. The P‐CFs possess a large specific surface area and one‐dimensional porous structure, offering facile storage and fast transport channels for K+ ions. When used as an anode for KIBs, the P‐CFs exhibit a high reversible specific capacity of 275 mAh·g−1 at a current density of 0.1 A·g−1 after 500 cycles and even retain a capacity of 100 mAh·g−1 after 5000 cycles at 2 A·g−1. This study demonstrates a simple strategy for the low‐cost synthesis of nitrogen‐doped porous carbon fibers from an environmental friendly biomaterial, with excellent electrochemical performance as an anode for KIBs.

Keywords

• anodes
• biomass‐derived carbonization
• porous carbon
• potassium ion batteries