Growth of Flower-like MnO2 on Porous ZIF-67 for Achieving Enhanced Supercapacitive Properties

Abstract

Zeolitic imidazolate framework (ZIF)-supported flower-like porous MnO2 (ST@ZIF-67/MnO2) was fabricated through SiO2-guided preparation of the ZIF precursor and subsequent in situ synthesis and deposition of MnO2. The specific porous structure can effectively shorten the ion transport channels, expose more active sites, and improve the tolerance toward volume expansion during the cyclic process, thus resulting in enhanced supercapacitive properties. Typically, the ST@ZIF-67/MnO2-based electrode delivered a high specific capacitance of 278.6 F g–1 at 0.5 A g–1, which is almost 10 times that of pristine ZIF-67 and 1.5 times that of the composite without using the SiO2 template (ZIF-67/MnO2). Additionally, the electrode showed good electrochemical cycling stability with 80.3% retention after 10, 000 cycles at 10 A g–1. Our strategy of growing porous transition metal oxides on ZIFs provides a viable pathway for developing efficient electrode materials for energy storage devices.