Covalently binding ultrafine MoS₂ particles to N, S co-doped carbon renders excellent Na storage performances

MoS₂ has attracted much interest for the potential application in sodium-ion batteries (SIBs) anodes because of the high theoretical capacity and electrochemical activity with Na. However, poor electrochemical performance caused by severe volume variations during the charge/discharge processes limits its practical application. Herein, we present an elaborately designed architecture comprising ultrafine MoS₂ nanoparticles covalently bonded to N, S co-doped carbon (MoS₂/NSC) via an in situ solid-state growth process, which displays high-capacity Na storage, fast sodiation/desodiation kinetics, and substantially mitigated volume fluctuations. As a consequence, MoS₂/NSC delivers outstanding Na storage performances including a high reversible capacity of 340 mA h g⁻¹ at 100 mA g⁻¹ and a rate capacity of 208 mA h g⁻¹ at 2000 mA g⁻¹. Further assembling with a Na₃V₂(PO₄)₃/C cathode, the full-cell delivers a specific capacity of 238 mA h g⁻¹ after 80 cycles at 50 mA g⁻¹, demonstrating the great potential of our MoS₂/NSC electrode. Density function theory calculations manifest that NSC not only presents strong binding to MoS₂ but also significantly decreases the Na ion diffusion energy barrier, thus leading to robust structure stability and fast electrode kinetics. This study may open a new and efficient avenue for developing advanced MoS₂ anodes for SIBs.