Flexible energy storage devices based on nanocomposite paper

TLDR

Recent interest in ultrathin, flexible, safe energy storage devices drives the need to integrate multiple electrochemical components into single units to meet modern gadget demands. The study demonstrates that electrode, separator, and electrolyte can be integrated into contiguous nanocomposite units to serve as building blocks for thin, mechanically flexible energy storage devices. The authors use nanoporous cellulose paper embedded with aligned carbon nanotube electrodes and electrolytes as the basic unit to construct flexible supercapacitors, batteries, hybrids, and dual‑storage battery‑in‑supercapacitor devices. The freestanding nanocomposite paper devices exhibit full mechanical flexibility during operation, support supercapacitors with aqueous, ionic liquid, and bioelectrolytes across record temperature ranges, and offer unprecedented design flexibility for devices across diverse temperatures and environments.

Abstract

There is strong recent interest in ultrathin, flexible, safe energy storage devices to meet the various design and power needs of modern gadgets. To build such fully flexible and robust electrochemical devices, multiple components with specific electrochemical and interfacial properties need to be integrated into single units. Here we show that these basic components, the electrode, separator, and electrolyte, can all be integrated into single contiguous nanocomposite units that can serve as building blocks for a variety of thin mechanically flexible energy storage devices. Nanoporous cellulose paper embedded with aligned carbon nanotube electrode and electrolyte constitutes the basic unit. The units are used to build various flexible supercapacitor, battery, hybrid, and dual-storage battery-in-supercapacitor devices. The thin freestanding nanocomposite paper devices offer complete mechanical flexibility during operation. The supercapacitors operate with electrolytes including aqueous solvents, room temperature ionic liquids, and bioelectrolytes and over record temperature ranges. These easy-to-assemble integrated nanocomposite energy-storage systems could provide unprecedented design ingenuity for a variety of devices operating over a wide range of temperature and environmental conditions.