Ma Ting, Li Cheng-Han, Thakur Ratul Mitra, Tabor Daniel P, Lutkenhaus Jodie L
Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, USA.
Department of Chemistry, Texas A&M University, College Station, TX, USA.
Nat Mater. 2023 Apr;22(4):495-502. doi: 10.1038/s41563-023-01518-z. Epub 2023 Mar 27.
Metal-free aqueous batteries can potentially address the projected shortages of strategic metals and safety issues found in lithium-ion batteries. More specifically, redox-active non-conjugated radical polymers are promising candidates for metal-free aqueous batteries because of the polymers' high discharge voltage and fast redox kinetics. However, little is known regarding the energy storage mechanism of these polymers in an aqueous environment. The reaction itself is complex and difficult to resolve because of the simultaneous transfer of electrons, ions and water molecules. Here we demonstrate the nature of the redox reaction for poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl acrylamide) by examining aqueous electrolytes of varying chao-/kosmotropic character using electrochemical quartz crystal microbalance with dissipation monitoring at a range of timescales. Surprisingly, the capacity can vary by as much as 1,000% depending on the electrolyte, in which certain ions enable better kinetics, higher capacity and higher cycling stability.
无金属水系电池有可能解决预计出现的战略金属短缺问题以及锂离子电池中存在的安全问题。更具体地说，氧化还原活性非共轭自由基聚合物是无金属水系电池的有前景的候选材料，因为这类聚合物具有高放电电压和快速的氧化还原动力学。然而，对于这些聚合物在水性环境中的能量存储机制却知之甚少。由于电子、离子和水分子的同时转移，该反应本身很复杂且难以解析。在这里，我们通过在一系列时间尺度上使用具有耗散监测功能的电化学石英晶体微天平，研究具有不同促溶剂/向心溶剂特性的水性电解质，来证明聚（2,2,6,6 - 四甲基哌啶氧基 - 4 - 基丙烯酰胺）的氧化还原反应性质。令人惊讶的是，根据电解质的不同，容量变化可达1000%，其中某些离子能实现更好的动力学、更高的容量和更高的循环稳定性。
