Machinable Carbon X-Aerogels for Batteries and Electrochemical Capacitors
Development of three-dimensional (3D) structures for energy storage devices is a major focus of research. Carbon aerogels are a unique class of 3D materials with high surface area, high electrical conductivity, and continuous open porosity. In particular, for supercapacitors, their 3D interconnected networks with open pores act as reservoirs of electrolyte and provide low-resistance pathways for ion transport. However, they have an inherent weakness: brittleness resulting from their skeleton morphology, which limits their use in applications where mechanical strength and durability are required. To this end, we have developed carbon x-aerogels, a special class of polymer-cross-linked aerogels, which are produced by incorporating a conformal polymer coating on the aerogel framework through cross-linking. Our carbon x-aerogels are not only porous and conductive, but also mechanically robust with high compressibility and fast recovery. Notably, they can be further manufactured into thin slices by cutting; we call this property "machinable".
We have investigated the carbon x-aerogels as electrodes for supercapacitors and their performance is highlighted by high volumetric capacitance, which results from the densely packed electroactive structure in three dimensions. We continue studying these materials as electrodes for batteries, such as lithium- or sodium-sulfur, metal-air batteries, etc. We aim to increase the battery capacity and stability by optimizing the x-aerogel structure and incorporating various metals or metal oxides into the aerogel framework.