Harnessing biological insights: Integrating proton regulation, pH buffer and zincophility for highly stable Zn anode

Abstract

Zinc anodes are severely threatened by hydrogen evolution, dendrite growth and by-products. Inspired by the mechanisms of L-carnosine (L-car) in maintaining intracellular pH stability and fostering mucosal repair in biological systems, this study innovatively proposed a comprehensive strategy integrating proton regulation, pH buffer and zincophility by introducing L-car as an electrolyte additive to achieve remarkable stability of zinc anode. Experimental validations and theoretical calculations demonstrate that the abundant N and O sites in L-car can form robust hydrogen bonds with protons, effectively impeding interfacial proton transport and substantially mitigating HER. Moreover, dual pH buffering sites of L-car facilitate dynamic modulation of proton concentration, stabilizing the pH of electrolyte, and suppressing Zn corrosion/passivation/by-product. Concurrently, the robust chelation between L-car and Zn2+ orchestrates uniform zinc ion deposition. This synergistic trifecta of L-car endows Zn ion batteries with an extraordinary cycling stability, extending to an ultralong duration of 5500 h. Furthermore, the Zn//MnO2 full battery, demonstrates remarkable stability, retaining a specific capacity of 106.1 mAh/g with 79.2 % retention after 1000 cycles at 3 A/g. This study pioneers the interdisciplinary application of L-car in electrolyte modification, presenting a novel paradigm for stabilizing zinc anodes.