A Novelly Hierarchical LDHs−Based Cathode with Reduced Deprotonation Barrier Toward High−Performance Alkaline Energy Storage

Abstract

Abstract Layered double hydroxides (LDHs) are promising electrode materials for alkaline electrochemical energy storage (EES). However, their low capacity, sluggish rate performance, and limited cycle life significantly hinder practical applications. This study unlocks the direct deprotonation reaction pathway for LDH materials through theoretical calculations. Guided by this insight, a novelly hierarchical composite (LDH−TPA) with various dimensions and components is fabricated by introducing terephthalic acid (TPA), serving as a superior cathode material for alkaline EES devices. Experimental results and theoretical investigations reveal the transformation process for metal–organic framework quantum dots (MOF−QDs) and the enhanced mechanism of reaction kinetics in the LDH−TPA electrode. Benefiting from the reduced deprotonation barrier, optimized electronic structure, and fast electrons/ions transport rates, the LDH−TPA1 electrode demonstrates a high specific capacity of 267 mAh g −1 at 1 A g −1 and retains 167 mAh g −1 even at 20 A g −1 , along with excellent cycling stability. Furthermore, an alkaline nickel−zinc battery (AZB) with LDH−TPA1 cathode is assembled, achieving a lifespan exceeding 3400 cycles, and a high energy density of 341.3 Wh kg −1 at a power density of 1640.9 W kg −1 . This study is expected to provide new insight into the modification of LDHs and the advancement of alkaline energy systems.