2D Graphene/MnO Heterostructure with Strongly Stable Interface Enabling High‐Performance Flexible Solid‐State Lithium‐Ion Capacitors
Wenjie Liu, Xiong Zhang, Yanan Xu, Lei Wang, Zhao Li, Chen Li, Kai Wang, Xianzhong Sun, Yabin An, Zhong‐Shuai Wu, Yanwei Ma
Abstract
Abstract The delicate structural engineering is widely acknowledged as a powerful tool for boosting the electrochemical performance of conversion‐type anode materials for lithium storage. Here, a general electrostatic self‐assembly strategy is proposed for the in situ synthesis of MnO nano‐cabbages on negatively charged reduced graphene oxide (rGO/MnO). The strong interfacial heterostructure and robust lithium storage mechanism related to fast Li + diffusion kinetics and high Li‐adsorption ability of rGO/MnO heterostructure are confirmed through operando experimental characterizations and theoretical calculation. Owing to the rapid charge transfer, enriched reaction sites, and stable heterostructure, the as‐synthesized rGO/MnO anode delivers a high capacity (860 mAh g −1 at 0.1 A g −1 ), superior rate capability (211 mAh g −1 at 10 A g −1 ), and cycle stability. Notably, the as‐assembled flexible pouch cell of activated carbon//rGO/MnO solid‐state lithium‐ion capacitors (LICs) possesses an exceptional energy density of 194 Wh kg −1 and power density of 40.7 kW kg −1 , both of which are among the highest flexible solid‐state LICs reported so far. Further, the LICs possess an ultralong life span with ≈77.8% retention after 10 000 cycles and extraordinary safety, demonstrative of great potential for practical applications.