Ab initio investigation of layered MoS2 electrodes for aqueous zinc batteries via interlayer engineering

Rechargeable zinc batteries with aqueous electrolytes have traditionally suffered from inferior electrochemical and kinetic performance due to poor accommodation of zinc within the electrodes. Engineered transition metal dichalcogenides (TMDs), with their tunable interlayer spacings, are a promising class of materials for the electrodes to address these limitations, offering potential for fast atomic transport and effective intercalation. Here we investigate in detail the atomic scale mechanism of aqueous zinc intercalation in a prototypical layer-expanded TMD, MoS 2 . Using systematic first principles density functional theory simulations, we show that the presence of water molecules within bulk unmodified MoS 2 decreases stability and diffusion kinetics of intercalated zinc. Optimisation of interlayer distances improves the kinetics in all cases. 1T-MoS 2 retains a stable calculated voltage of 0.8 V, showing suitability as the anode material, while 2H-MoS 2 has poor stability above zinc concentrations of 0.03 per MoS 2 formula unit. 1T-MoS 2 is thermodynamically favourable above zinc concentrations of 0.25 zinc per MoS 2 formula unit at all engineered interlayer distances, with a specific capacity of 232 mAh g −1 . The key findings of the study advance the understanding of the trade-off between electrochemical capacity and kinetics, thus highlighting an approach to improved anodic performance of MoS 2 for aqueous zinc batteries. • Electrochemistry of layered MoS 2 is investigated for aqueous Zn-ion batteries. • Water hinders many aspects of Zn electrochemistry in 2H and 1T MoS 2 . • Optimisation of interlayer enables 1T-MoS 2 useful performance as Zn-ion electrode.