Carbon/C3N4 heterostructures constructed from lignin toward enhanced lithium-ion storage

Lithium-ion batteries (LIBs) are widely used in portable energy storage. The capacity of commercial graphite is difficult to improve due to the stoichiometry limit of LiC 6 of graphite, thus new anodes need to be developed to meet the demand of high-energy–density LIB. The growing interest in graphitized carbon nitride (g-C 3 N 4 ) stems from its structural resemblance to graphite and its capacity to offer abundant adsorption and intercalation sites. However, g-C 3 N 4 , as a semiconductor, has a low lithium transfer rate due to its poor conductivity and high diffusion resistance. Improving the electron transport rate of g-C 3 N 4 and reducing the adsorption energy barrier of Li + in g-C 3 N 4 are the keys to improving the electrochemical performances of g-C 3 N 4 . In this study, lignin and melamine were homogeneously mixed using the spray drying method, followed by the preparation of covalently bonded C 3 N 4 /LC material through a one-step carbonization process. The uniform dispersion of g-C 3 N 4 in amorphous carbon can improve the conductivity and reduce the diffusion energy barrier of Li + . As a result, the C 3 N 4 /LC-x anode has better electrochemical behavior, including higher reversible capacity, better rate performance, and cycle stability.