“Anchoring Capture” Effect Mimicking Proline in Hardy Deep-Sea Fish to Stabilize the Zinc Anode with Lower Operating Temperature

Abstract

The low plating/stripping efficiency of zinc anodes, dendrite growth, and high freezing points of aqueous solutions hinder the practical application of aqueous zinc-ion batteries. This paper proposes a zwitterionic permeable network solid-state electrolyte based on the “anchor-capture” effect to address these problems by incorporating proline (Pro, a biological antifreeze agent) into the electrolyte. Extensive validation tests, Quantum Chemistry (QC) calculations, Molecular Dynamics (MD) Simulations, and ab initio molecular dynamics simulations consistently indicate that the amino groups in proline adsorb onto the Zn metal surface, stabilizing the zinc anode-electrolyte interface, suppressing side reactions from water decomposition, and homogenizing zinc-ion flux. This electrolyte demonstrates excellent reversibility in Zn-Mn₂O₃ cells and Zn-Zn half-cells, achieving a high coulombic efficiency of over 99.4% across 2000 cycles in Zn-Mn₂O₃ full cells, and delivering a discharge-specific capacity of 175.2 mAh g⁻¹ at −35 °C and 1 A g⁻¹. Additionally, an appropriate concentration of proline lowers the electrolyte's freezing point to −45 °C through the network's solid-state effect, ensuring the stable operation of the solid-state battery at −35 °C. This innovative concept of network solid-state electrolytes injects new vitality into the development of multifunctional solid-state electrolytes.