Boron and phosphorous co-doped porous carbon as high-performance anode for sodium-ion battery

Abstract

Sodium-ion batteries (SIBs) have attracted extensive attention as the important replacement for lithium-ion batteries, due to the nature abundance of sodium sources. The key to high-performance SIBs lies in appropriate anode material with sufficient space and sites for the diffusion and adsorption of sodium ion (Na+). Heteroatom doping in carbon has proven to be an effective strategy to improve the electrochemical performance of carbon-based anodes for SIB. The feasible preparation of doped carbon is essential for the development of SIBs. Here, boron (B) and phosphorous (P) co-doped honeycomb-like carbon (BPC) has been synthesized by one-step pyrolysis of onium salts containing B and P. Benefiting from dual doping of B and P in carbon, the increased layer space, defects and electrical conductivity of BPC enhance the adsorption capability of Na+, mass transport and charge diffusion. The formed porous structure in BPC can promote the electrolyte penetration as well as buffer the volume changes during cycling. When employed as the anode material for SIBs, high storage capacity and excellent cycle life have been enabled. This contribution paves a feasible and controlled approach to prepared heteratom-doped carbons for Na+ storage.