Eco-friendly micro-supercapacitors using fallen leaves?
Femtosecond micro-supercapacitors on a single leaf could easily be
applied to wearable electronics, smart houses, and IoTs

Date:
January 27, 2022
Source:
The Korea Advanced Institute of Science and Technology (KAIST)
Summary:
A research team has developed a graphene-inorganic-hybrid micro-
supercapacitor made of leaves using femtosecond direct laser writing
lithography. The advancement of wearable electronic devices is
synonymous with innovations in flexible energy storage devices. Of
the various energy storage devices, micro-supercapacitors have drawn
a great deal of interest for their high electrical power density,
long lifetimes, and short charging times.



FULL STORY ==========================================================================
A KAIST research team has developed a graphene-inorganic-hybrid micro- supercapacitor made of leaves using femtosecond direct laser writing lithography. The advancement of wearable electronic devices is synonymous
with innovations in flexible energy storage devices. Of the various
energy storage devices, micro-supercapacitors have drawn a great deal
of interest for their high electrical power density, long lifetimes,
and short charging times.


========================================================================== However, there has been an increase in waste battery generation with
the increases in the consumption and use of electronic equipment as
well as the short replacement period that follows advancements in mobile devices. The safety and environmental issues involved in the collection, recycling, and processing of such waste batteries are creating a number
of challenges.

Forests cover about 30 percent of the Earth's surface, producing a huge
amount of fallen leaves. This naturally occurring biomass comes in
large quantities and is both biodegradable and reusable, which makes
it an attractive, eco- friendly material. However, if the leaves are
left neglected instead of being used efficiently, they can contribute
to fires or water pollution.

To solve both problems at once, a research team led by Professor Young-Jin
Kim from the Department of Mechanical Engineering and Dr. Hana Yoon from
the Korea Institute of Energy Research developed a one-step technology
that can create porous 3D graphene micro-electrodes with high electrical conductivity without additional treatment in atmospheric conditions
by irradiating femtosecond laser pulses on the surface of the leaves
without additional materials. Taking this strategy further, the team
also suggested a method for producing flexible micro-supercapacitors.

They showed that this technique could quickly and easily produce porous graphene-inorganic-hybrid electrodes at a low price, and validated their performance by using the graphene micro-supercapacitors to power an LED
and an electronic watch that could function as a thermometer, hygrometer,
and timer.

These results open up the possibility of the mass production of flexible
and green graphene-based electronic devices.

Professor Young-Jin Kim said, "Leaves create forest biomass that comes
in unmanageable quantities, so using them for next-generation energy
storage devices makes it possible for us to reuse waste resources,
thereby establishing a virtuous cycle." This research was published
in Advanced Functional Materials last month and was sponsored by the
Ministry of Agriculture Food and Rural Affairs, the Korea Forest Service,
and the Korea Institute of Energy Research.

========================================================================== Story Source: Materials provided by The_Korea_Advanced_Institute_of_Science_and_Technology_ (KAIST). Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Truong‐Son Dinh Le, Yeong A. Lee, Han Ku Nam, Kyu Yeon Jang,
Dongwook Yang, Byunggi Kim, Kanghoon Yim, Seung‐Woo
Kim, Hana Yoon, Young‐Jin Kim. Green Flexible
Graphene-Inorganic‐Hybrid Micro‐Supercapacitors Made
of Fallen Leaves Enabled by Ultrafast Laser Pulses. Advanced
Functional Materials, 2021; 2107768 DOI: 10.1002/ adfm.202107768 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/01/220127104214.htm

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