Electronic Structure Modulation and Substance Transfer Acceleration Induced by Synchronous Construction of a Tri-Functional Electrocatalyst with Host-Guest Role Swapping in Deformable Solid-State Zinc-Air Batteries

Abstract

Zinc-air batteries (ZABs) assembled with iron-decorated multifunctional oxygen catalysts have emerged as promising contenders for energy storage and conversion systems. However, sluggish and multi-protonated redox steps and restricted electron/ion transfer pathways have hampered their commercialization. Herein, these challenges are addressed by synchronously constructing BN-supported FeP (FeP-BN) oxygen electrocatalysts employing an active site switching strategy to create ZABs that can simultaneously improve oxygen reaction kinetics, mass transfer dynamics, and tolerance. The strong coupling between FeP and BN substrates modulates the electronic structure of the active site and optimizes the adsorption/desorption behaviors of oxygen-containing intermediates, thereby significantly lowering the energy barrier of the rate-determining step of the oxygen reduction/evolution reaction (ORR/OER). Consequently, the as-prepared FeP-BN electrode possess remarkable oxygen electrocatalytic activity with high half-wave potential (0.94 V) for ORR and low overpotential (224 and 80 mV) at 10 mA cm-2 for OER and hydrogen evolution reaction (HER). Furthermore, the assembled flexible solid-state ZABs in sandwich configuration obtains a maximum power density of 87.20 mW cm-2, an extraordinary stability over 210 cycles, and a high round-trip efficiency of 62.31%. This research provides novel insights into the rational design of multifunctional electrocatalysts with host-guest role swapping and paves the way for their commercial implementation in wearable devices.

Keywords: FeP-BN, multifunctional electrocatalysts, host-guest role swapping, Zn-air batteries