Unveiling the "Proton Lubricant" Chemistry in Aqueous Zinc-MoS 2 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 MoS 2 -based AZIBs. Herein, we innovatively prepared a MoS 2 /poly(3,4-ethylenedioxythiophene) (MoS 2 /PEDOT) hybrid, where the intercalated PEDOT not only increases the interlayer spacing (from 0.62 to 1.29 nm) and electronic conductivity of MoS 2 , but also activates the proton insertion chemistry. Thus, highly efficient and reversible H + /Zn 2+ co-insertion/extraction behaviors are demonstrated for the first time in aqueous Zn-MoS 2 batteries. More intriguingly, the co-inserted protons can act as lubricants to effectively shield the electrostatic interactions between MoS 2 /PEDOT host and divalent Zn 2+ , enabling the accelerated ion-diffusion kinetics and exceptional rate performance. This work proposes a new concept of "proton lubricant" driving Zn 2+ transport and broadens the horizons of Zn-MoS 2 batteries.