| Work Detail |
Researchers at the Global University Network used cheap and abundant starting materials to synthesize a small-molecule organic electrode material and achieved significant performance gains with various battery chemistries. The new cathode material exhibited cycle stability, ultra-high capacity, and speed capability unprecedented in aqueous zinc-ion batteries.
Most energy storage devices use toxic and expensive transition metals as electrode materials. Lithium-ion batteries are based on metals such as cobalt and nickel, known to cause skin irritations, allergies and even cancer.
Scientists from the World University Network have embarked on a research project to develop conductive electrode materials with very low amounts of toxic metals. They have synthesized porous polymeric materials based on abundant and environmentally friendly components such as battery electrodes. They have also designed ionic-conductive functional materials as solid-state electrolytes to improve electrochemical performance.
Their key result was the development of a conjugated quinone (HATAQ) hexaazatrianthranylene (HATA) small molecule organic electrode material. By introducing quinone conjugates into the electron-deficient hexaazatriphenylene-derived nucleus, HATAQ, with highly extended p-conjugation, demonstrated its potential to produce very high metal ion storage capacity.
“Organic electrode materials have many advantages, such as low cost and environmental friendliness,” explains Professor Watchareeya Kaveevivitchai of Taiwans National Cheng Kung University (NCKU). "They also contain a large number of redox active sites capable of undergoing a multi-electron transfer process at a redox potential that, if properly tuned, can give rise to high energy density."
Inspired by HATAQs excellent electrochemical performance in lithium-ion batteries, researchers have studied the compound as a cathode in other known safer and cheaper rechargeable battery systems, such as those based on sodium, zinc and other multivalents.
Specifically, in aqueous zinc ion rechargeable cells with a 1M ZnSO4 solution as the electrolyte, the large number of redox active sites and extended conjugation enabled HATAQ to deliver an ultra-high capacity of 492 mAh g-1 at 50 mA g-1 and an excellent rate capacity of up to 20 A g-1 with a reversible capacity of 199 mAh g-1 corresponding to a 99% retention after 1,000 cycles.
The researchers claim that HATAQs performance is one of the best ever recorded in aqueous zinc ion cells. The results are reported in the article “ Proton-enabled biomimetic stabilization of small-molecule organic cathode in aqueous zinc-ion batteries ”, recently published in Journal of Materials Chemistry A. |
