Evening dresses with woven LEDs may look extravagant, but the light sources need a constant power supply from devices that are equally good portable, durable and lightweight. Chinese scientists have manufactured fibrous electrodes for portable devices that are flexible and distinguishable with their high energy density. The key to the preparation of the electrode material was a microfluidic technique, as shown in the journal Angewandte Chemie .
Dresses that emit glittering light from hundreds of small LEDs can create eye-catching effects in ballrooms or fashion shows. But wearable electronics can also mean sensors integrated into functional fabrics to monitor, for example, water evaporation or temperature changes. Energy storage systems that operate such portable units must combine deformability with high capacity and durability. However, deformable electrodes often fail in long-term operation, and their capacity lags behind that of other state-of-the-art energy storage devices.
Electrode materials usually draw a fine balance between porosity, conductivity and electrochemical activity. Materials researcher Su Chen, Guan Wu, and their team from Nanjing Tech University, China, have looked more deeply into the material requirements for flexible electrodes and developed a porous hybrid material synthesized from two carbon nanomaterials and a metal-organic framework. The nanocarbons provided the large surface area and excellent electrical conductivity, and the metal-organic framework provided the porous structure and electrochemical activity.
To make the electrode materials flexible for portable applications, the micro-mesoporous carbon frames were spun into fibers with a thermoplastic resin using an innovative blow-blowing machine. The resulting fibers were pressed into tablecloths and mounted in supercapacitors, although it was found that a further coating round with the micro-mesoporous carbon frames further improved electrode performance.
The supercapacitors made of these electrodes were not only deformable, but could also contain higher energy density and greater specific capacities than comparable units. They were stable and endured more than 1
The authors pointed out that microfluidic drip-based synthesis was the key to improving the performance of the electrode materials for portable electronics. It was about adapting the perfect porous nanostructure, they argued.
Using high energy density materials in electrode design improves lithium-sulfur batteries
Hengyang Cheng et al, Hierarchical micro-mesoporous carbon framework-based hybrid nanofibers for high density capacitive energy storage, Angewandte Chemie International Edition (2019). DOI: 10.1002 / anie.201911023
Flexible, portable supercapacitors based on porous nanocarbon nanocomposites (2019, October 18)
Retrieved October 18, 2019
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