Toward fast zinc-ion storage of MoS2 by tunable pseudocapacitance

While aqueous rechargeable zinc ion batteries (ARZIBs) are one of the promising energy storage devices, it is still a challenge to develop satisfactory cathode materials. Here, a hierarchical hybrid where MoS2 nanosheets with 86% of 1T phase are grown in-situ on reduced graphene oxide scaffolds is proposed to be a superior cathode of ARZIBs. The microstructure of as-prepared hybrid is correlated with its zinc storage performance by electrochemical and spectroscopic characterizations coupled with electron microscopy analysis. They reveal the incorporation of reduced graphene oxide scaffolds effectively stabilizes the 1T phase, exempting, to the maximum, the phase transition associated with the zinc insertion/extraction, reduces the electron transfer resistance and keeps the hierarchical morphology of the nanoscale MoS2 that shortens the zinc ion diffusion path length. All these together develop the pseudocapacitive property of MoS2. As a result, this hybrid electrode delivers a high discharge capacity of 108.3 mAh g−1 at 5.0 A g−1 and retains 88% initial capacity after 1000 cycles. Our strategy sheds some lights on the rational design of MoS2 nanoscale architecture towards superior cathode material of divalent/multivalent aqueous batteries.