A highly stretchable triboelectric nanogenerator with both stretch-insensitive sensing and stretch-sensitive sensing

It is an inevitable requirement for stretchable triboelectric nanogenerators to be able to sense external mechanical forces and convert them into observable electrical signals under adverse conditions (twisting, stretching, etc.). However, the vast majority of existing stretchable triboelectric nanogenerators have an inherent limitation that they cannot obtain stable contact triboelectric response under stretching deformation. Here, we propose a highly stretchable dual-mode triboelectric nanogenerator (SDTENG) with both stretch-insensitive sensing and stretch-sensitive sensing properties. By the regional modulus modulation based on cross-linked interpenetrating network (IPN), our SDTENG shows almost the same pressure sensing property represented by the triboelectric output in the 120% stretch range, mainly because the effective contact region of the friction layer is high modulus and stretch-unperturbed. While in the low modulus region, the MXene/CNT electrode of SDTENG exhibits excellent strain sensitivity with the stretching of the device, and the gauge factor is up to 238.8. The combination of stretch-insensitive pressure sensing and stretch-sensitive strain sensing makes our SDTENG with promising potential applications in wearable devices and smart robots.