A universal method towards conductive textile for flexible batteries with superior softness

Abstract

High flexibility, as one target for wearable batteries, requires each component of battery devices to be soft. However, softness, as an index reflecting the soft degree, was seldom applied in battery field. Here, several metal-deposited soft substrates, including cloth, paper and sponge were produced using a universal electroless plating method. High conductivity (4~200 kS m^‒1) and high coverage of active materials was achieved without sacrificing the softness (~8 mm) of cotton cloth. Given such a visible value, the softness of the total battery device can be tuned. Consequently, batteries based on these metal-conductive cloths show excellent performance and high softness. The assembled Ag cloth//Zn battery delivered a stable output of 1.0 mAh cm^‒2 with a softness of 4.21 mm. The Ni cloth//Zn battery provided a high discharge capacity of 0.98 mAh cm^‒2 at 4 mA cm^‒2 with a high discharge plateau around 1.7 V (energy density of 1.7 mWh cm^–2 at a power density of 8.5 mW cm^–2). Moreover, a large size (360 cm²) of flexible Ni cloth//Zn device with a softness of 3.34 mm and discharge capacity of 132 mAh is fabricated and mounted on a human cloth to power electronics.