Nonlinear Conductive Materials for Adaptive Electric Overstress Control: Theory, Tailoring and Applications

Artificial intelligence computing, renewable energy integration and transportation electrification are driving electrical and electronic equipment towards higher power densities, higher voltage ratings and greater miniaturisation. Under these trends, insulation systems have become a key bottleneck for reliability and compactness. Conventional approaches, including enhancing the dielectric strength of uniform materials and geometric‐field grading, are approaching their limits because of trade‐offs between performance and processability, as well as sensitivity to manufacturing tolerances and long‐term parameter drift. In this context, nonlinear conductivity materials (NCMs) provide a promising solution by enabling self‐adaptive electric‐field grading through field‐dependent conductivity, thereby suppressing local field concentrations while maintaining low leakage current under normal operation. This review summarises recent progress in NCMs, focusing on conduction mechanisms, property‐tailoring strategies and representative applications. Furthermore, this review also highlights critical scientific and technological challenges in material design and engineering implementation. Addressing these hurdles is essential for establishing NCMs as a robust, enabling solution for the next generation of intelligent, miniaturised and high‐performance electrical and electronic devices.