Qin Zili, Li Xilong, Dong Qi, Qi Kaiwen, Chen Shiyuan, Zhu Yongchun
School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, 230026, P. R. China.
Small. 2024 Aug;20(32):e2400108. doi: 10.1002/smll.202400108. Epub 2024 Mar 21.
Aqueous rechargeable proton batteries are attractive due to the small ionic radius, light mass, and ultrafast diffusion kinetics of proton as charge carriers. However, the commonly used acidic electrolyte is usually very corrosive to the electrode material, which seriously affects the cycle life of the battery. Here, it is proposed that decreasing water activity and limiting proton concentration can effectively prevent side reactions of the MoO anode such as corrosion and hydrogen precipitation by using a lean-water hydrogel electrolyte. The as-prepared polyacrylamide (PAAM)-poly2-acrylamide-2-methylpropanesulfonic acid (PAMPS)/MnSO (PPM) hydrogel electrolyte not only has abundant hydrophilic groups that can form hydrogen bonds with free water and inhibit solvent-electrode interaction, but also has fixed anions that can maintain a certain interaction with protons. The assembled MoO||MnO full battery can stably cycle over 500 times for ≈350 h with an unprecedented capacity retention of 100% even at a low current density of 0.5 A g. This work gives a hint that limiting free water as well as proton concentration is important for the design of electrolytes or interfaces in aqueous proton batteries.
水系可充电质子电池因其质子作为电荷载体的离子半径小、质量轻和超快扩散动力学而备受关注。然而，常用的酸性电解质通常对电极材料具有很强的腐蚀性，这严重影响了电池的循环寿命。在此，提出通过使用贫水凝胶电解质降低水活性并限制质子浓度，可以有效防止MoO负极的诸如腐蚀和析氢等副反应。所制备的聚丙烯酰胺（PAAM）-聚2-丙烯酰胺-2-甲基丙烷磺酸（PAMPS）/MnSO₄（PPM）水凝胶电解质不仅具有丰富的亲水基团，能够与自由水形成氢键并抑制溶剂-电极相互作用，而且具有固定阴离子，能够与质子保持一定的相互作用。组装的MoO₂||MnO₂全电池即使在0.5 A g⁻¹的低电流密度下也能稳定循环超过500次，约350小时，前所未有的容量保持率为100%。这项工作表明，限制自由水以及质子浓度对于水系质子电池中电解质或界面的设计至关重要。
