Molecular Connectors Boosting the Performance of MoS2 Cathodes in Zinc‐Ion Batteries

Abstract

AbstractZinc‐ion batteries (ZIBs) are promising energy storage systems due to high energy density, low‐cost, and abundant availability of zinc as a raw material. However, the greatest challenge in ZIBs research is lack of suitable cathode materials that can reversibly intercalate Zn2+ ions. 2D layered materials, especially MoS2‐based, attract tremendous interest due to large surface area and ability to intercalate/deintercalate ions. Unfortunately, pristine MoS2 obtained by traditional protocols such as chemical exfoliation or hydrothermal/solvothermal methods exhibits limited electronic conductivity and poor chemical stability upon charge/discharge cycling. Here, a novel molecular strategy to boost the electrochemical performance of MoS2 cathode materials for aqueous ZIBs is reported. The use of dithiolated conjugated molecular pillars, that is, 4,4′‐biphenyldithiols, enables to heal defects and crosslink the MoS2 nanosheets, yielding covalently bridged networks (MoS2‐SH2) with improved ionic and electronic conductivity and electrochemical performance. In particular, MoS2‐SH2 electrodes display high specific capacity of 271.3 mAh g−1 at 0.1 A g−1, high energy density of 279 Wh kg−1, and high power density of 12.3 kW kg−1. With its outstanding rate capability (capacity of 148.1 mAh g−1 at 10 A g−1) and stability (capacity of 179 mAh g−1 after 1000 cycles), MoS2‐SH2 electrodes outperform other MoS2‐based electrodes in ZIBs.