Amino oxidized sodium alginate-based humidity-resistant triboelectric nanogenerator for human motion and respiration monitoring

The charge dissipation effect induced by the surrounding water not only severely reduces the output of the triboelectric nanogenerators (TENGs), but also impacts their stability and durability, significantly limiting their application. Therefore, developing humidity-resistant triboelectric nanogenerators (HRTENGs) is an urgent issue to improve the environmental adaptability of TENGs. Herein, a novel HRTENG was designed with amino-oxidized sodium alginate (OSAN) that achieves enhanced electrical output properties from 15% RH to 85% RH, accompanying excellent reversible property and outstanding water resistance ability. The enhancing dielectric property by introducing of aldehyde groups direct improves the output of the TENG, and the hydrophilicity improvement by modified with the amino side chains induces the formation of bound water, resulting in charge dissipation effect weakening and contact charging strengthening, further increasing the output of the HRTENG. At 50% RH, the electrical output of the HRTENG fabricated with OSAN₃G_0.5 is nine times compared to the TENG made with SAG_0.5. The HRTENGs were used to monitor motion and respiratory status and could also clearly identify sleep issues for patients suffering from obstructive sleep apnea-hypopnea syndrome. The HRTENG we constructed provides a reference for future wearable self-powered devices for motion management, respiratory monitoring, disease diagnosis, and rehabilitation treatment.