One-Step Synthesis of Monolithic All-in-One Structural Supercapacitor

Significant advancements in energy storage have been achieved over the past few decades. However, the increasing demand for mobile electronics, electric vehicles, and portable devices highlights the urgent need for higher energy capacity and more efficient storage solutions. To overcome the limitations of conventional technologies, researchers are actively exploring novel materials and design strategies. Structural energy storage devices offer a promising solution by integrating energy storage directly into structural components, reducing the weight and/or volume otherwise required for separate storage units. Potential applications range from electric vehicles and microsatellites to architectural applications.

Nowadays, conventional approaches, particularly for rigid structural energy storage devices, enhance mechanical strength by incorporating reinforcement materials such as carbon fibers and epoxy resin. While these materials improve structural integrity, they significantly limit energy storage capacity, posing a major challenge to achieving truly multifunctional performance.

This study introduces an intrinsically multifunctional structural supercapacitor with nanoporous amorphous carbon (NAC) electrodes and a ceramic fiber separator, fabricated via a one-step spark plasma sintering (SPS) process. The device exhibits a flexural modulus of 8.34 GPa and a high volumetric capacitance of 26.8 F/cm^{<span style="font-size:10.8333px">3</span>} (980 mF/cm^{<span style="font-size:10.8333px">2</span>}), with an energy density of 45 Wh/L. The enhancements in energy storage capacity arise from the absence of inactive reinforcement materials. Additionally, the binder-free interlocking interface significantly improves structural stability over laminated structures without compromising storage capacity. As a result, the device achieves a multifunctional efficiency of 9.95, surpassing existing solutions. This strategy not only addresses key limitations in structural supercapacitors but also offers new possibilities for next-generation energy storage systems.