A research team collaborating with Yamanashi University and Waseda University in Japan has developed an all solid-state air battery using proton exchange membranes as electrolytes and organic compounds with redox activity as negative electrodes. This type of battery can be repeatedly charged and discharged, is lightweight and safe, and can be used even in a bent state. It is expected to be applied to portable electronic devices.
At present, common air batteries are generally composed of oxygen in the air as the positive active substance, metals such as lithium as the negative active substance, and water-based electrolytes. Because there is no need to store positive electrode active substances inside the battery, air batteries theoretically have a higher energy density. However, existing air batteries often use solution electrolytes, which may cause safety issues such as electrolyte leakage. In addition, metals used as negative electrodes are prone to performance degradation under the action of oxygen and water in the environment.
To address the above issues, researchers from two universities collaborated and attempted to use organic compounds with oxidation-reduction activity, 2,5-dihydroxy-1,4-benzoquinone, and their polymers as negative electrode active substances, proton exchange membranes as electrolytes, and gas diffusion electrodes containing platinum catalysts as positive electrodes, with oxygen as the active substance, to form all solid-state air batteries.
Through current and potential measurements, researchers confirmed the reaction and reversibility that occurred at the negative electrode of the battery, and evaluated the discharge rate, charge discharge cycle performance, etc. of the battery. Research has shown that using organic compounds with redox activity as negative electrodes for air batteries is a feasible approach. Compared to using 2,5-dihydroxy-1,4-benzoquinone as the negative electrode of the battery, using the polymer of this compound as the negative electrode can significantly improve the discharge capacity of the battery. At a discharge rate of 15C, the charge and discharge cycles of an all solid-state air battery using a polymer of 2,5-dihydroxy-1,4-benzoquinone as the negative electrode can reach 30 times.
Compared to the commonly used air batteries at present, this new type of all solid-state air battery has higher safety and uses materials that do not contain moisture, which will not lead to a decrease in electrode performance due to moisture. In the future, by improving material performance and durability, this type of battery is expected to be used as a power source for portable electronic devices such as mobile phones.
