A 4 V-class metal-free organic lithium-ion battery gets closer to
reality
Date:
April 13, 2022
Source:
Tohoku University
Summary:
Organic, metal free, high-energy batteries are a pathway to a
greener future. Yet scientists have struggled to find ways to
boost the voltage in organic lithium-ion batteries. Now, a study
has proposed a small organic molecule known as croconic acid that
can maintain a working voltage of around 4 Volts.
FULL STORY ==========================================================================
A joint research team from Tohoku University and the University of
California, Los Angeles (UCLA) has made a significant advancement towards high-voltage metal-free lithium-ion batteries that use a small organic molecule, croconic acid. The breakthrough moves us closer to realizing metal-free, high-energy, and inexpensive lithium-ion batteries.
========================================================================== Unlike conventional lithium-ion batteries, which depend on rare-earth
materials such as cobalt and lithium, organic batteries exploit naturally abundant elements such as carbon, hydrogen, nitrogen, and oxygen. In
addition, organic batteries have greater theoretical capacities than conventional lithium-ion batteries because their use of organic materials renders them lightweight. Most reported organic batteries to date,
however, possess a relatively low (1-3V) working voltage. Increasing
organic batteries' voltage will lead to higher energy density batteries.
Itaru Honma, a professor of chemistry at Tohoku University's Institute of Multidisciplinary Research for Advanced Materials, Hiroaki Kobayashi,
an assistant professor of chemistry at Tohoku University, and Yuto
Katsuyama, a graduate student at UCLA, found that croconic acid, when
used as a lithium-ion battery cathode material, maintains a strong
working voltage of around 4 V.
Croconic acid has five carbon atoms bonded to each other in a pentagonal
form, and each of the carbons is bonded to oxygen. It also has a
high theoretical capacity of 638.6 mAh/g, which is much higher than
the conventional lithium-ion battery cathode materials (LiCoO2 ~ 140
mAh/g). "We investigated the electrochemical behavior of croconic acid
in the high-voltage range above 3 V using theoretical calculations and electrochemical experiments," said Kobayashi. "We discovered that croconic
acid stores lithium ions at roughly 4 V, giving a very high theoretical
energy density of 1949 Wh/kg, which is larger than most inorganic and
organic lithium-ion batteries." Although the theoretical capacity was
not achieved in this study, the researchers are optimistic this can be
enhanced by the development of stable electrolytes at high-voltage and
chemical modifications to croconic acid. Since most electrolytes cannot
stand for such a strong working voltage of croconic acid, developing
new electrolytes is vital. Additionally, the structures of small organic molecules, including croconic acid, can be easily modified.
Appropriate structural modification can stabilize the molecule, leading
to greater capacity and reversibility.
========================================================================== Story Source: Materials provided by Tohoku_University. Note: Content
may be edited for style and length.
========================================================================== Journal Reference:
1. Yuto Katsuyama, Hiroaki Kobayashi, Kazuyuki Iwase, Yoshiyuki
Gambe, Itaru
Honma. Are Redox‐Active Organic Small Molecules
Applicable for High‐Voltage (>4 V) Lithium‐Ion
Battery Cathodes? Advanced Science, 2022; 2200187 DOI:
10.1002/advs.202200187 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/04/220413090855.htm
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