Self-powered, frost-resistant, and antimicrobial hydrogel with high open-circuit voltage for flexible device energy supply and stimuli feedback

Self-powered hydrogels have gained attention for addressing energy needs of small flexible devices, but creating ones with high voltage and current remains challenging. Here, we report a novel polyacrylamide hydrogel loaded with copper sulfate and ammonium chloride (PAC), which not only exhibits good mechanical properties (maximum strain of 390 %), high conductivity (conductivity of 2.37 S/m), but also possesses excellent antibacterial and antifreeze properties. PAC demonstrates remarkable stimulus responsiveness. When using resistance variation as the output signal, its GF value reaches as high as 5.3 within the strain range of 35 % to 280 %. Additionally, PAC can utilize current variation as an output signal, providing options for various sensor applications. On the other hand, PAC hydrogels can achieve self-powering capabilities through zinc electrodes, with an open-circuit voltage of 0.92 V. By connecting PAC hydrogels in parallel or series, higher output voltage and current can be achieved, providing a strong guarantee for powering small devices. In a stacked series configuration, 8 sets of PACs can generate an output voltage of 7.16 V and an output current of 52.6 mA. In sum, PAC is a high-performance self-powered hydrogel with tremendous potential in the fields of flexible sensing and energy supply.