Self-Powered, Long-Durable, and Highly Selective Oil–Solid Triboelectric Nanogenerator for Energy Harvesting and Intelligent Monitoring

The as-designed triboelectric nanogenerator (TENG) generates an excellent electric output, which is an order of magnitude higher than that of TENGs made from commercial dielectric materials. The as-designed TENG-based sensor can detect worn debris in oils at least down to 0.01 wt% and water contamination down to 100 ppm, which are much better than other online monitoring methods (particle > 0.1 wt%; water > 1000 ppm). A high-selective monitoring system is successfully developed for distinguishing water contamination from the multi-mixed contaminants in lubricating oils.