Aqueous all-polymer proton cells (APPBS) consisting of redox active polymer electrodes are considered safe and clean renewable energy storage**. However, it is still a great challenge for APPBS to maximize the high battery output voltage within the narrow electrochemical window of the aqueous electrolyte while subjecting to high current rates.
Jilin University: Chao Danming, Jia XiaotengAn all-polymer aqueous proton battery with excellent electrochemical properties was developed by using catechol-based cathode and quinone-based polyurethane (PUQ) anode.
Fig.1. Schematic diagram of the polymer electrode and redox reaction of an all-polymer proton battery
By introducing the biomimetic redox-active catechol overhangs into the poly(3,4-ethoddioxythiophene) (PEDot) backbone, a high redox potential (060 V vs AGCl) cathode, which is attributed to significant electron delocalization. The electron cloud separation of the redox overhangs and the conjugated backbone facilitates the pseudocapacitive charge storage, resulting in excellent rate performance. In addition, diffusion quinone-based polymer anodes with hard and soft segments can increase the overpotential and reduce electrode rupture caused by volume changes, thereby improving cycling stability.
Fig.2. Structural characterization of polymer electrodes under different charge-discharge states
Therefore, in combination with the diffusion quinone-based polymer anode, APPBS provides 0High cell voltage of 72 V, excellent rate performance (from 0.).The volume retention rate from 5 to 25 A g-1 is 648%) and cycle stability (capacity retention rate of more than 80% after 1000 cycles at 2 A g-1), which is better than the most advanced organic proton full battery. In addition, DFT calculations and ex situ structural characterization can deepen the understanding of proton storage mechanisms in quinone-based polymer electrodes. These results highlight the feasibility of rationally designing high-performance polymer electrodes for sustainable energy storage systems.
Fig.3. Performance of aqueous all-polymer proton batteries
bioinspired catechol-grafting pedot cathode for an all-polymer aqueous proton battery with high voltage and outstanding rate capacity. advanced science 2021. doi: 10.1002/advs.202103896