Molten salt splitting of CO2 with CaC2 and in-situ nitrogen doping for carbon anode of lithium/sodium-ion batteries

Abstract

Carbon materials are the most attractive anodes for high-energy–density lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). Herein, a molten salt method is developed to split CO2 with CaC2 for N-doped carbon anodes of LIBs and SIBs. Molten salt accelerates the carbonization and the in-situ N doping in kinetics. The carbon materials are characterized as large specific surface, porous and low graphite degree. The graphitization and functional groups are promoted by the doping of N atoms. These structure characteristics improve the battery performance, including high specific capacity, good rate performance and excellent cycle stability. The CN60–4 h anode delivers a reversible capacity of 448 mAh·g−1 over 500 cycles at 0.5 A·g−1 and 155 mAh·g−1 over 2000 cycles at 10 A·g−1 for the anode of LIBs and SIBs, respectively. This work offers an easy and feasible method for preparing N-doped carbon anode materials for LIBs and SIBs.