Low-polarity organic molecules intercalated in MoS2 with enhanced structural stability for advanced zinc ion batteries

Despite the significant potential of layered molybdenum disulfide (MoS₂) as a cathode material for aqueous zinc-ion batteries (ZIBs), its electrochemical performance is hindered by challenges including volume expansion, low conductivity, and dissolution during prolonged charging/discharging cycles. Herein, a universal strategy of incorporating low-polarity organic molecules into the interlayer of MoS₂ is reported to stabilize the structure and enhance conductivity, thus addressing these issues. Through experimental and theoretical analyses, the insertion of representative guest n-butanol (n-BuOH) triggers a phase transition from semiconducting 2H-MoS₂ to metallic 1T-MoS₂, accompanied by a reduction in desolvation energy and ion diffusion barriers, thereby accelerating reaction kinetics. Additionally, the strong interaction between n-BuOH and Mo⁴⁺ effectively stabilizes the MoS₂ framework, while the soft alkyl chain of n-BuOH synergistically decreases the interfacial strain and mitigates the volume expansion during the cycling process. Consequently, the prepared n-BuOH inserted MoS₂ (n-Bu-MoS₂) delivers a high-rate capability (236.5 mAh g⁻¹ at 0.3 A g⁻¹ with 104.9 mAh g⁻¹ at 5 A g⁻¹) and exceptional cycle stability (95.6 % capacity retention after 300 cycles at 1 A g⁻¹). Moreover, various experimental results demonstrate the phase transition between 2H and 1T-MoS₂ during the energy storage process. This work provides new insights into the employment of low-polarity organic guests to enhance the electrochemical performance of MoS₂.