Bio-inspired hormonic electrolyte: negative feedback for ultra-stable zinc anodes

Abstract

Zn-based batteries have been considered as promising alternatives for Li-ion batteries, in terms of high safety, low cost and rich natural resources. Unfortunately, their practical application is greatly limited by irreversible dendrite growth and low utilization of Zn. We overcome these issues by implementing a self-regulating negative feedback electrolyte, mimicking hormones in the coagulation system. The “hormone” remodels the Zn²⁺ coordination microenvironment and dynamically adsorbs on initial inhomogeneous Zn tips, which spontaneously repels Zn²⁺ and shields H₂O molecules, thus constantly deteriorating the uneven electric field distribution and dynamically preventing Zn dendrites and side reactions. Such a negative feedback electrolyte enables Zn//Zn cells to stably cycle for 240 h at 20 mA cm⁻²/10 mA h cm⁻² (85.5% depth of discharge) and 50 mA cm⁻²/20 mA h cm⁻² (68.3% depth of discharge), which are drastically improved compared with those without the “hormone” (<10 h). Our negative feedback electrolyte provides rich possibilities for developing practical dendrite-free metal batteries.