Wearable Antifreezing Fiber-Shaped Zn/PANI Batteries with Suppressed Zn Dendrites and Operation in Sweat Electrolytes.

Fiber-shaped Zn batteries are promising candidates for wearable electronics owing to their high energy and low cost, but further studies are still required to address the issues related to detrimental Zn dendrite growth and limited low-temperature performances. Here, we report an antifreeze, long-life, and dendrite-free fiber-shaped Zn battery using both nanoporous Zn and polyaniline (PANI) electrodeposited on carbon nanofibers (CFs) as the cathode and anode, respectively. The fiber-shaped Zn anode achieves stable plating/stripping for 1000 mAh cm-2 accumulative capacity with low polarization (30 mV) at a current density of 2 mA cm-2. The dendrite-free Zn electrodes also enable the stable cycling of the fiber battery with 75.1% capacity retention after 1000 cycles. With an antifreeze agent added in the gel electrolyte, the fiber battery maintains excellent performance at temperatures as low as -30 °C. Lastly, by utilizing the doping/dedoping mechanism of Cl- in the PANI electrode, we achieve, for the first time, a Zn battery using human sweat as a harmless electrolyte. Our work provides a long-life and antifreeze fiber-shaped battery that is highly promising for future wearable energy storage devices.

Textile Triboelectric Nanogenerators Simultaneously Harvesting Multiple "High-Entropy" Kinetic Energies.

Distributed renewable kinetic energies are ubiquitous but with irregular amplitudes and frequencies, which, as one category of "high-entropy" energies, are crucial for next-generation self-powered electronics. Herein, we present a flexible waterproof dual-mode textile triboelectric nanogenerator (TENG), which can simultaneously scavenge multiple "high-entropy" kinetic energies, including human motions, raindrops, and winds. A freestanding-mode textile TENG (F-TENG) and a contact-separation-mode textile TENG (CS-TENG) are integrated together. The structure parameters of the textile TENG are optimized to improve the output performances. The raindrop can generate a voltage of up to ∼4.3 V and a current of about ∼6 µA, while human motion can generate a voltage of over 120 V and a peak power density of ∼500 mW m-2. The scavenged electrical energies can be stored in capacitors for powering small electronics. Therefore, we demonstrated a facile preparation of a TENG-based energy textile that is highly promising for kinetic energy harvesting and self-powered electronics.