Zn-ion ultrafluidity via bioinspired ion channel for ultralong lifespan Zn-ion battery

Abstract

ABSTRACT Rechargeable aqueous Zn-ion batteries have been deemed a promising energy storage device. However, the dendrite growth and side reactions have hindered their practical application. Herein, inspired by the ultrafluidic and K+ ion-sieving flux through enzyme-gated potassium channels (KcsA) in biological plasma membranes, a metal-organic-framework (MOF-5) grafted with –ClO4 groups (MOF-ClO4) as functional enzymes is fabricated to mimic the ultrafluidic lipid-bilayer structure for gating Zn2+ ‘on’ and anions ‘off’ states. The MOF-ClO4 achieved perfect Zn2+/SO42− selectivity (∼10), enhanced Zn2+ transfer number (${{t}_{{\rm{Z}}{{{\rm{n}}}^{2 + }}}} = 0.88$) and the ultrafluidic Zn2+ flux (1.9 × 10−3 vs. 1.67 mmol m−2 s−1 for KcsA). The symmetric cells based on MOF-ClO4 achieve a lifespan of over 5400 h at 10 mA cm−2/20 mAh cm−2. Specifically, the performance of the PMCl-Zn//V2O5 pouch cell keeps 81% capacity after 2000 cycles at 1 A g−1. The regulated ion transport, by learning from a biological plasma membrane, opens a new avenue towards ultralong lifespan aqueous batteries.