Japanese researchers have developed an all-solid-state rechargeable air battery (SSAB) using redox-active organic particles for the negative electrode and a proton-conductive polymer as the strong electrolyte, showcasing enhanced performance and durability. This ingenious method has possible implications for improving battery life in electronics and advancing toward a carbon-free society.
In this first-of-its-kind battery, a benzoquinone-based unfavorable electrode is utilized along with a strong Nafion polymer electrolyte.
Metals typically work as the active materials for the negative electrodes in batteries. Nevertheless, theres been a shift towards using redox-active organic molecules like quinone- and amine-based substances as unfavorable electrodes in rechargeable metal– air batteries, which feature oxygen-reducing positive electrodes.
Here, protons and hydroxide ions take part in the redox reactions. Such batteries exhibit high efficiency, near to the optimum capacity that is in theory possible. In addition, using redox-active organic molecules in rechargeable air batteries conquers issues connected with metals, including the development of structures called dendrites, which impact battery efficiency, and have negative environmental effect.
Researchers have actually developed an all-solid-state rechargeable air battery with a dihydroxy-benzoquinone-based natural negative electrode and Nafion polymer electrolyte. Credit: Kenji Miyatake from Waseda University
These batteries utilize liquid electrolytes– simply like metal-based batteries– which posture major security concerns like high electrical resistance, leaching results, and flammability.
Such batteries display high performance, close to the optimum capacity that is theoretically possible. Using redox-active natural particles in rechargeable air batteries overcomes issues associated with metals, including the development of structures called dendrites, which effect battery performance, and have negative environmental effect.
“To the finest of my understanding, no air batteries based on organic electrodes and strong polymer electrolytes have actually been established yet,” says Miyatake.
They found that, unlike common air batteries that use a metal negative electrode and an organic liquid electrolyte, the SSAB did not deteriorate in the existence of water and oxygen. “This technology can extend the battery life of small electronic gizmos such as smart devices and eventually contribute to recognizing a carbon-free society,” concludes Miyatake.
Now, in a brand-new research study just recently released in Angewandte Chemie International Edition, a group of Japanese scientists have developed an all-solid-state rechargeable air battery (SSAB) and investigated its capacity and resilience. The study was led by Professor Kenji Miyatake from Waseda University and the University of Yamanashi, and co-authored by Professor Kenichi Oyaizu from Waseda University
The scientists picked a chemical called 2,5-dihydroxy-1,4- benzoquinone (DHBQ) and its polymer poly( 2,5-dihydroxy-1,4- benzoquinone-3,6- methylene) (PDBM) as active products for the negative electrode due to their reversible and stable redox responses in acidic conditions. In addition, they utilized a proton-conductive polymer called Nafion as the strong electrolyte, thereby changing standard liquid electrolytes. “To the best of my understanding, no air batteries based upon natural electrodes and strong polymer electrolytes have been developed yet,” states Miyatake.
After the SSAB remained in place, the researchers experimentally examined its charge– discharge efficiency, rate qualities, and cyclability. They found that, unlike typical air batteries that use a metallic negative electrode and a natural liquid electrolyte, the SSAB did not weaken in the presence of water and oxygen. Furthermore, replacing the redox-active molecule DHBQ with its polymeric equivalent PDBM formed a better negative electrode. While the per gram-discharge capacity of the SSAB-DHBQ was 29.7 mAh, the matching value of the SSAB-PDBM was 176.1 mAh, at a consistent existing density of 1 mAcm-2.
The battery, which utilizes a polymeric dihydroxy-benzoquinone-based negative electrode and a Nafion-based strong electrolyte, shows high Coulombic effectiveness and discharge capacity. Credit: Kenji Miyatake from Waseda University.
The scientists also discovered that the coulombic performance of SSAB-PDBM was 84% at a 4 C rate, which slowly decreased to 66% at a 101 C rate. While the discharge capability of SSAB-PDBM was minimized to 44% after 30 cycles, by increasing the proton-conductive polymer material of the negative electrode, the researchers might considerably improve it to 78%. Electron tiny images confirmed that the addition of Nafion enhanced the efficiency and resilience of the PDBM-based electrode.
This research study demonstrates the successful operation of an SSAB comprising redox-active natural molecules as the negative electrode, a proton-conductive polymer as the solid electrolyte, and an oxygen-reducing, diffusion-type positive electrode. The researchers hope that it will pave the method for further advancements. “This technology can extend the battery life of small electronic gizmos such as smartphones and ultimately contribute to understanding a carbon-free society,” concludes Miyatake.
Reference: “All-Solid-State Rechargeable Air Batteries Using Dihydroxybenzoquinone and Its Polymer as the Negative Electrode” by Makoto Yonenaga, Yusuke Kaiwa, Kouki Oka, Kenichi Oyaizu and Kenji Miyatake, 2 May 2023, Angewandte Chemie International Edition.DOI: 10.1002/ anie.202304366.
The research study was moneyed by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan, and JKA promotion funds from AUTORACE.
