Applications of nanomaterials in micro-supercapacitors and their performance enhancement mechanisms

Abstract

With the development of flexible electronics and wearable devices, micro energy storage devices are subject to increasingly stringent requirements for high power output, rapid response, and long-term stable operation. Despite their advantages of rapid charge/discharge capability, high power density, and long cycling stability, micro-supercapacitors (MSCs) still face challenges in practical applications due to their limited energy density, sluggish ion transport, and insufficient structural stability. To address these challenges, nanomaterials can enhance MSC performance by enhancing electron transport, ion diffusion, and interfacial charge storage. Specifically, carbon materials build conductive networks and facilitate ion transport; metal oxides and conductive polymers boost charge storage via pseudocapacitive reactions; and two-dimensional materials such as MXene accelerate charge transfer and interfacial reactions due to their high conductivity and abundant active sites. This review summarizes the charge storage mechanisms and key challenges of MSCs, highlighting the performance optimization of carbon-based materials, metal oxides/conductive polymers, and MXene-based composites, and exploring the relationship between nanocomposite structure and MSC performance. The results show that nanomaterial structural and compositional optimization improves electron/ion transport and interfacial charge storage, thus leading to enhanced energy density, power performance, and cycling stability of MSCs.