KSCN molten salt synthesis of hierarchical MoS2/NPC for rapid and durable sodium storage

Abstract

MoS₂ boasts high capacity but often encounters issues such as poor electrical conductivity, limited cycling stability due to volume expansion, and polysulfide shuttling when applied as the anode in sodium-ion batteries (SIBs). To this end researchers have developed MoS₂/carbon composites, which enhance electronic conductivity, ion diffusion, and structural stability. Herein, we develop a new synthesis method using a KSCN molten salt to produce hierarchical MoS₂ on nitrogen and phosphorus co-doped carbon (NPC). The molten KSCN acts both as the sulfur source and the reaction medium, facilitating the creation of hierarchical MoS₂ structures with a high loading of 85.8 wt%. These structures optimize ion diffusion channels and enhance electrochemical reaction kinetics. Additionally, the NPC framework improves electron transport and reduces polysulfide shuttling. With its superior structural stability and accelerated electrode kinetics, MoS₂/NPC exhibits an impressive rate capacity of 468 mAh g⁻¹ at 10 A g⁻¹ and maintains a long lifespan of 1300 cycles at 2 A g⁻¹. Moreover, full cells equipped with a NaNi_1/3Fe_1/3Mn_1/3O₂ cathode retain 98 % capacity retention after 400 cycles. This study presents a promising approach for fabricating advanced MoS₂/carbon anodes with dedicate nanostructures for SIBs.