In Situ Encapsulation of SnS 2 /MoS 2 Heterojunctions by Amphiphilic Graphene for High-Energy and Ultrastable Lithium-Ion Anodes.

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 SnS 2 /MoS 2 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 MoS 2 can promote the reaction kinetics and suppress heterointerface passivation by forming a building-in-electric field, thereby enhancing the reversible conversion of Sn to SnS 2 . Consequently, the SnS 2 /MoS 2 /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 0.8 Co 0.1 Mn 0.1 )O 2 (NCM811) cathode is paired with the prelithiated SnS 2 /MoS 2 /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.