In-situ fabrication of carbon-metal fabrics as freestanding electrodes for high-performance flexible energy storage devices

Hierarchical 1D carbon structures are attractive due to their mechanical, chemical andelectrochemical properties however the synthesis of these materials can be costly andcomplicated. Here, through the combination of inexpensive acetylacetonate salts of Ni,Co and Fe with a solution of polyacrylonitrile (PAN), self-assembling carbon-metalfabrics (CMFs) containing unique 1D hierarchical structures can be created via easyand low-cost heat treatment without the need for costly catalyst deposition nor adangerous hydrocarbon atmosphere. Microscopic and spectroscopic measurementsshow that the CMFs form through the decomposition and exsolution of metalnanoparticle domains which then catalyze the formation of carbon nanotubes throughthe decomposition by-products of the PAN. These weakly bound nanoparticles formstructures similar to trichomes found in plants, with a combination of base-growth, tipgrowthand peapod-like structures, where the metal domain exhibits a core(graphitic)-shell(disorder) carbon coating where the thickness is in-line with the metal-carbonbinding energy. These CMFs were used as a cathode in a flexible zinc-air battery whichexhibited superior performance to pure electrospun carbon fibers, with their metallicnanoparticle domains acting as bifunctional catalysts. This work therefore unlocks apotentially new category of composite metal-carbon fiber based structures for energystorage applications and beyond