Piezoionic SnSe Nanosheets-Double Network Hydrogel for Self-Powered Strain Sensing and Energy Harvesting

Flexible strain sensors have enormous potential in wearable devices, robots, and health monitoring equipment. However, the poor stretchability of strain sensors based on semiconductors and the low sensitivity of resistance change-based hydrogel strain sensors hinders the comprehensive application. Herein, a flexible piezoionic SnSe-hydrogel composite with an optimized structure and improved performance is designed. The piezoionic output rises nonlinearly as the applied force increases, with the piezoionic coefficient up to 1780 nV Pa⁻¹ and −7.21 nA Pa⁻¹. The composite can realize the continuous positioning in 1D space based on the piezoionic effect. It also demonstrates self-powered characteristics, an ultrafast response speed of 6–8 ms, and a high gauge factor of 95.89. The sensor is exemplified to monitor fist clenching and finger bending, which has the potential to discriminate different joint movements. Meanwhile, the device can light up a light–emitting diode under pressure and bending. The as-prepared piezoionic SnSe-hydrogel device, having both high stretchability and sensitivity, may shed light on developing high-performance flexible strain sensors and generators.     

SnSe nanoplates swallowed in carbon nanofibers as the self-standing anode for lithium-ion and sodium batteries with enhanced performance

SnSe is a promising anode candidate for both lithium-ion and sodium batteries (LIBs and SIBs) with high theoretic capacities, low toxicity and abundant resources. However, it suffers a short cycling life due to the poor conductivity and volume expansion when used as anode material. To improve its Li/Na storage properties, SnSe nanoplates are encapsulated in carbon nanofibers formation a 3D conductive network via a moderate electrostatic spinning and heat treatment. The modified SnSe anode exhibits textile-like feature with extensively mechanical flexibility, and was directly used as anode without and additives for both LIBs and SIBs. It delivers an excellent cycle performance with a high capacity (598 mA h g^?1 after 400 cycles for LIBs and 240 mA h g^?1 after 250 cycles for SIBs), which are modify enhanced comparing with reported works. The effective strategy can provide an available approach to build self-standing and flexible architecture, which is beneficial for the design of electrode materials for SIBs.