Ultra-durable and flexible fibrous mild quasi-solid-state Ag–Zn batteries with Na2SO4 electrolyte additive

Silver–zinc (Ag–Zn) batteries are regarded as a promising power source for flexible and wearable electronics due to their high safety, high energy density, and steady output voltage. However, the weak flexibility and poor cycle performance significantly limit the practical use of Ag–Zn batteries. In this work, we propose a novel flexible fibrous quasi-solid-state mild Ag–Zn battery with superb cycling performance by using a mild electrolyte and highly flexible binder-free electrodes. Carbon nanotube fibers serve as the current collector to improve the flexibility of flexible Ag–Zn cells. The mild electrolyte containing ZnCl2 and Na2SO4 not only prevents the dissolution of the Ag cathode but also impedes the heterogeneous growth of Zn dendrites. With 1500 cycles at 1 A g−1, the fibrous quasi-solid-state mild Ag–Zn battery achieves a remarkable capacity retention of 93.1%. Moreover, this novel flexible quasi-solid-state mild Ag–Zn battery can deliver a high capacity of 103.51 mA h g−1 at 0.1 A g−1. The fibrous quasi-solid-state mild Ag–Zn battery demonstrates remarkable flexibility and excellent bending ability (after 600 bending cycles with capacity retention of 89%). This pioneering work sheds light on the establishment of high-performance quasi-solid-state mild Ag–Zn batteries for burgeoning wearable electronics.