High‐Rate Na‐Ion Storage Enabled by Metal–Nitrogen–Carbon (M–N–C) Charge Transfer Bridges

Due to the large ionic radius of sodium ions, which leads to inferior electrochemical kinetics and rate performance, the applications of sodium-ion batteries are limited. In this study, nickel sulfide nanoparticles are uniformly dispersed within nitrogen- and sulfur-co-doped carbon nanosheets (Ni/NSC) via a unique synthetic method, facilitated by strong nickel-nitrogen bonds (Ni─N bonds). The resultant Ni─N bonds provide a synergistic effect, which not only enhances charge transfer but also suppresses volume changes, thereby ensuring structural stability and high-efficiency energy storage. Meanwhile, the composite material integrates the advantages of both components: the thin carbon nanosheets containing dopants enhance the diffusion pathways for sodium ions, while the integrated NiS nanocrystals form an electronic transport network, ensuring stability during charge-discharge cycling. As a result, the composite material exhibits high reversible capacity and significant rate performance at high current densities, offering a promising strategy for the development of high-rate electrode materials.