Construction of MoS2/C Hierarchical Tubular Heterostructures for High-Performance Sodium Ion Batteries

Molybdenum disulfide (MoS2) has been considered to be a promising anode material for sodium ion batteries (SIBs), because of its high capacity and graphene-like layered structure. However, irreversible conversion reaction during the sodiation/desodiation process is a major problem that must be overcome before its practical applications. In this work, MoS2/amorphous carbon (C) microtubes (MTs) composed of heterostructured MoS2/C nanosheets have been developed via a simple template method. The existence of MoS2/C heterointerface plays a key role in achieving high and stable performance by stabilizing the reaction products Mo and sulfide phases, providing fast electronic and Na+ ions diffusion mobility, and alleviating the volume change. MoS2/C MTs exhibit a high reversible specific capacity of 563.5 mA h g–1 at 0.2 A g–1, good rate performance (520.5, 489.4, 452.9, 425.1, and 401.3 mA h g–1 at 0.5, 1.0, 2.0, 5.0, and 10.0 A g–1, respectively), and excellent cycling stability (484.9 mA h g–1 at 2.0 A g–1 after 1500 cycles).

二硫化钼（MoS₂）凭借其高容量与类石墨烯层状结构，被视为极具应用前景的钠离子电池（SIBs）负极材料。然而，在钠化/脱钠过程中发生的不可逆转化反应，是其迈向实用化进程中必须攻克的核心瓶颈。本研究通过简易模板法，制备得到由异质结构MoS₂/C纳米片构成的二硫化钼/非晶碳（amorphous carbon, C）微管（MTs）。MoS₂/C异质界面的存在可通过稳定反应产物金属钼与硫化物相、加速电子与钠离子扩散迁移、缓解体积膨胀效应，对实现高性能且稳定的电化学性能起到关键作用。该MoS₂/C微管展现出优异的电化学性能：在0.2 A g⁻¹的电流密度下，可逆比容量可达563.5 mA h g⁻¹；具备良好的倍率性能，在0.5、1.0、2.0、5.0及10.0 A g⁻¹电流密度下，比容量分别为520.5、489.4、452.9、425.1及401.3 mA h g⁻¹；同时拥有出色的循环稳定性，在2.0 A g⁻¹电流密度下循环1500圈后，比容量仍可维持在484.9 mA h g⁻¹。