Hierarchical K‐Birnessite‐MnO<sub>2</sub> Carbon Framework for High‐Energy‐Density and Durable Aqueous Zinc‐Ion Battery
Guolong Wang, Yaling Wang, Boyuan Guan, Jiamei Liu, Yan Zhang, Xiaowei Shi, Cheng Tang, Guohong Li, Yingbo Li, Xiao Wang, Lei Li
Abstract
Abstract MnO 2 ‐based material is one of the most promising cathode candidates of aqueous zinc‐ion batteries (ZIBs), but its commercialization is hindered by the sluggish reaction kinetics and poor structural stability. Herein, a hierarchical framework consisting of core–shell structured carbon nanotubes@K‐birnessite‐MnO 2 enwrapped by graphene/carbon black bicomponent networks (CNT@KMO@GC) via a simple method for ZIBs is designed and developed. The hierarchical framework characterized with favorable K + preintercalation, δ‐phase, and vertically aligned nanoflake arrays of KMO and 3D electrically conductive network shows the enhanced electronic/ionic conductivity and improved wettability with electrolyte, resulting in the fast charge/mass transport and stable structural stability of CNT@KMO@GC. When used as cathode in ZIBs, CNT@KMO@GC exhibits exciting electrochemical performance with remarkable capacity (405.5 mAh g −1 at 0.30 A g −1 ), high rate performance (166.6 mAh g −1 up to 10.0 A g −1 ), and impressive cycling stability (almost no capacity decay after 2000 cycles and 77.3% retention after 10 000 cycles at 10.0 A g −1 ). The energy storage mechanism of CNT@KMO@GC is clarified as H + /Zn 2+ coinsertion/extraction via electrochemical analysis and ex situ characterization. This study offers an innovative paradigm for the advance of ZIBs.