Scalable Self-Powered Sweat Lactate Patches Based on Bulk-Catalytic MXene/NiO for Wide-Range Detection

Lactate is a key marker of metabolic load, and sweat-based wearable sensors offer a non-invasive platform for assessing exercise intensity and fatigue. However, existing systems often rely on external power and face integration challenges. Here, we present a dispensing-printed, mass-producible, flexible, and self-powered non-enzymatic lactate sensing platform for real-time sweat analysis. We employ 2D MXene as a robust conductive scaffold for the in situ growth of NiO nanoparticles. This yields a self-supporting hybrid material with high electrical conductivity and electrocatalytic activity, making it ideal for both energy storage and enzyme-free sensing. Additionally, we elucidate the distinct sensing mechanisms of MXene/Ni(OH)₂ and MXene/NiO through spectroscopic and electrochemical analyses. Based on this design, we integrated large-area asymmetric micro-supercapacitors (MSCs) and flexible triboelectric nanogenerators (TENGs) with the MXene/NiO sensor to construct a fully self-powered system. In this architecture, the TENG harvests mechanical energy from body motion, the MSC stores and regulates the electrical energy, and the sensor reliably detects lactate over the physiologically relevant concentration range in human sweat. This integrated energy-harvesting-storage-sensing platform provides a general strategy for multifunctional nanomaterial and device design in wearable biosensing.