New Graphene electrodes for supercapacitors are close to lithium ion battery energy densities and can make all in one solar film and storage for self powering devices

A new graphene based electrode created by RMIT University researchers could boost the capacity of existing integrable storage technologies by 3000 per cent.

Theoretical analysis using an analytical equivalent circuit model shows that the enhancement of the areal capacitance is up to 300 times for Hilbert BFE electrodes compared to its planar electrode counterpart. The graphene-based prototype also opens a new path to the development of flexible thin film all-in-one solar capture and storage, bringing us one step closer to self-powering smart phones, laptops, cars and buildings.

The new electrode is designed to work with supercapacitors, which can charge and discharge power much faster than conventional batteries.

* the Hilbert supercapacitors retained 95% of capacitance even after 10,000 charge and discharge cycles
* the energy density of the Hilbert BFE-MSC is 30 times better than the reported LSG-MSCs and close to Li-ion batteries. Advanced super-resolution nanofabrication technique might bridge this gap

These results open a pathway for meeting the demands of the current technology like self-powered graphene energy storages for wearables and various self solar energy-powered devices, which will have a significant impact in various areas of human society.

 

The breakthrough electrode prototype (right) can be combined with a solar cell (left) for on-chip energy harvesting and storage.

Nature Scientific Reports – Bioinspired fractal electrodes for solar energy storages

Abstract

Solar energy storage is an emerging technology which can promote the solar energy as the primary source of electricity. Recent development of laser scribed graphene electrodes exhibiting a high electrical conductivity have enabled a green technology platform for supercapacitor-based energy storage, resulting in cost-effective, environment-friendly features, and consequent readiness for on-chip integration. Due to the limitation of the ion-accessible active porous surface area, the energy densities of these supercapacitors are restricted below ~3 × 10−3 Whcm−3. In this paper, we demonstrate a new design of biomimetic laser scribed graphene electrodes for solar energy storage, which embraces the structure of Fern leaves characterized by the geometric family of space filling curves of fractals. This new conceptual design removes the limit of the conventional planar supercapacitors by significantly increasing the ratio of active surface area to volume of the new electrodes and reducing the electrolyte ionic path. The attained energy density is thus significantly increased to ~10−1 Whcm−3- more than 30 times higher than that achievable by the planar electrodes with ~95% coulombic efficiency of the solar energy storage. The energy storages with these novel electrodes open the prospects of efficient self-powered and solar-powered wearable, flexible and portable applications.

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