A three-dimensional interconnected molybdenum disulfide/multi-walled carbon nanotubes cathode with enlarged interlayer spacing for aqueous zinc-ion storage

Layered molybdenum disulfide (MoS 2 ) shows tremendous prospect as cathode material for aqueous zinc-ion batteries (AZIBs) due to the two-dimensional zinc ions (Zn 2+ ) diffusion channels and tunable interlayer spacing. However, it is subjected to sluggish insertion/extraction kinetics, inferior electronic conductivity and inadequate active capacities. Herein, a three-dimensional (3D) interconnected MoS 2 /multi-walled carbon nanotubes (MWCNTs) framework is proposed to address these issues. Importantly, the MWCNTs cores offer interconnection routes for fast electrons and zinc ions transport, the expanded spacing of MoS 2 interlayer with 1.05 nm can facilitate rapid Zn 2+ intercalation/extraction, and the confined MoS 2 layers in inner MWCNTs can mitigate the agglomeration and restacking of MoS 2 nanosheets. Benefitting from the confined structural configuration, sufficient active surface and 3D structural stability, the MoS 2 /MWCNTs as AZIBs cathode delivers a large initial reversible capacity of 218.3 mAh/g and high coulombic efficiency of 78.2 % at 0.1 A/g. Additionally, the 3D interconnected cathode maintains nearly intact structure after a fierce galvanostatic charge/discharge process, resulting in large retained capacities of 126.3 mAh/g at 1 A/g after 650 cycles and 101.1 mAh/g at 3 A/g after 1000 cycles. This work offers a novel strategy for the structure design of two-dimensional materials to develop high-performance cathodes for AZIBs.