In Situ Encapsulation of SnS₂/MoS₂ Heterojunctions by Amphiphilic Graphene for High-Energy and Ultrastable...

Lithium-ion batteries with transition metal sulfides (TMSs) anodes promise a high capacity, abundant resources, and environmental friendliness, yet they suffer from fast degradation and low Coulombic efficiency. Here, a heterostructured bimetallic TMS anode is fabricated by in situ encapsulating SnS₂/MoS₂ nanoparticles within an amphiphilic hollow double-graphene sheet (DGS). The hierarchically porous DGS consists of inner hydrophilic graphene and outer hydrophobic graphene, which can accelerate electron/ion migration and strongly hold the integrity of alloy microparticles during expansion and/or shrinkage. Moreover, catalytic Mo converted from lithiated MoS₂ can promote the reaction kinetics and suppress heterointerface passivation by forming a building-in-electric field, thereby enhancing the reversible conversion of Sn to SnS₂. Consequently, the SnS₂/MoS₂/DGS anode with high gravimetric and high volumetric capacities achieves 200 cycles with a high initial Coulombic efficiency of >90%, as well as excellent low-temperature performance. When the commercial Li(Ni_0.8Co_0.1Mn_0.1)O₂ (NCM811) cathode is paired with the prelithiated SnS₂/MoS₂/DGS anode, the full cells deliver high gravimetric and volumetric energy densities of 577 Wh kg^-1 and 853 Wh L^-1, respectively. This work highlights the significance of integrating spatial confinement and atomic heterointerface engineering to solve the shortcomings of conversion-/alloying typed TMS-based anodes to construct outstanding high-energy LIBs.