Manganese Silicate Nanosheets for Quasi-Solid-State Hybrid Supercapacitors
Xuyang Jing, Yifu Zhang, Xueying Dong, Mu Yang, Changgong Meng
Abstract
Recently, manganese silicates have received much attention focusing on their synthesis and electrochemical properties. The synthesis mainly uses the expensive tetraethyl orthosilicate as a Si source and their electrochemical properties are far from the assumption. Herein, we develop a simple route for the synthesis of manganese silicate nanosheets (MS NSs) with excellent electrochemical properties, which are converted from the natural clay mineral magadiite as a silicon source. The structure and morphology characterizations demonstrate that the well-defined MS NSs are constructed using numerous nanosheets with a thickness of about 15 nm. The morphology of the nanosheets provides a huge number of active sites and effectively promotes the full contact between the material and the electrolyte. As a consequence, MS NSs possess a high specific capacitance of 514 F·g–1 at 0.5 A·g–1. The loose nanosheets can also shorten the ion diffusion distance and buffer structural stress during the charge/discharge process. So, the MS NSs exhibit an anticipated rate capability and long-term cycle stability for 98% capacitance after 10,000 cycles. The quasi-solid-state MS NSs//active carbon hybrid supercapacitor (MS NSs//AC HSC) devices deliver an area capacitance of 195 mF·cm–2 at 1 mA·cm–2 and an energy density of 0.88 Wh·m–2 at 2.25 W·m–2 with a superior cycle stability of approximately 100% after 10,000 cycles. The findings not only prove that magadiite can be a silicon source for synthesizing transition metal silicates as electrode materials for SCs but also open a potential application of natural clay minerals.