Unveiling the "Proton Lubricant" Chemistry in Aqueous Zinc-MoS₂ Batteries

Proton insertion chemistry in aqueous zinc-ion batteries (AZIBs) is becoming a research hotspot owing to its fast kinetics and additional capacities. However, H⁺ storage mechanism has not been deciphered in the popular MoS₂ -based AZIBs. Herein, we innovatively prepared a MoS₂ /poly(3,4-ethylenedioxythiophene) (MoS₂ /PEDOT) hybrid, where the intercalated PEDOT not only increases the interlayer spacing (from 0.62 to 1.29 nm) and electronic conductivity of MoS₂ , but also activates the proton insertion chemistry. Thus, highly efficient and reversible H⁺ /Zn²⁺ co-insertion/extraction behaviors are demonstrated for the first time in aqueous Zn-MoS₂ batteries. More intriguingly, the co-inserted protons can act as lubricants to effectively shield the electrostatic interactions between MoS₂ /PEDOT host and divalent Zn²⁺ , enabling the accelerated ion-diffusion kinetics and exceptional rate performance. This work proposes a new concept of "proton lubricant" driving Zn²⁺ transport and broadens the horizons of Zn-MoS₂ batteries.