Boosting\nAreal Capacitance and Energy Density of a\nFlexible Supercapacitor Based on High-Mass-Loading Layered Double\nHydroxides

Abstract

Flexible\nelectrodes with a high density of active material loading\nas well as abundant charge transfer channels are crucial for high-performance\nwearable energy storage devices, and their fabrication also remains\na great challenge. In this work, we report a hierarchical binder-free\nflexible electrode based on carbon nanosheets and a high-mass-loading\nCoNi-layered double hydroxide (11.8 mg cm^–2) core–shell\nstructure on the carbon clothe support (denoted as CC/CNs@CoNi-LDH).\nThe as-synthesized CC/CNs@CoNi-LDH electrode delivers a superior mass\nenergy density of 69.8 W h kg^–1, a power density\nof 4.3 kW kg^–1, and excellent stability with a retention\nof 91.1% of the initial capacitance even after 10,000 cycles. Moreover,\nex situ techniques including X-ray photoelectron spectroscopy, X-ray\ndiffraction, and Fourier transform infrared spectroscopy were carried\nout to identify the structure evolution and the electrochemical reaction\nmechanism of CC/CNs@CoNi-LDH. This work suggests a facile route to\nconstruct a binder-free electrode with a high-mass-loading, which\nis promising for the development of energy storage systems.