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锂离子电池中战略金属的预计短缺和安全问题。更具体地说，具有氧化还原活性的非共轭自由基聚合物因其高放电电压和快速氧化还原动力学而成为无金属水系电池的有前途的候选者。然而，关于这些聚合物在水性环境中的能量储存机制知之甚少。由于电子、离子和水分子的同时转移，反应本身很复杂且难以解决。在这里，我们展示了 poly(2,2,6, 6-tetramethylpiperidinyloxy-4-yl acrylamide) 通过使用电化学石英晶体微天平检查具有不同混沌/亲液特性的水性电解质，并在一定时间范围内进行耗散监测。令人惊讶的是，容量的变化可能高达 1,000%，具体取决于电解质，其中某些离子能够实现更好的动力学、更高的容量和更高的循环稳定性。