Advanced carbon-based nanostructured materials for energy storage devices

Commercially available batteries and capacitors normally use carbonaceous electrodes. However, since common graphite is often limited by its poor performances, alternative structures and morphologies could be developed. The possibility of exploiting innovative synthesis processes and virtuous alternative sources for advanced carbon-based materials opens new perspectives in a global scenario where the push for energy transition becomes progressively critical. Aiming at studying innovative pure or composites carbon materials for electrochemical devices, i.e. lithium-ion batteries and supercapacitors, this thesis includes the development of synthetic processes (i.e. following purely chemical routes or exploiting agricultural wastes), electrochemical testing, optimization of the device features, and a feasibility study of advanced characterization in operando. Hybrid C/Si anodes for lithium-ion batteries have been studied for many years. Carbon softness, conductivity, and capability of intercalating lithium ions are ideal to prevent the volumetric expansion of silicon lattice during cyclations. To obtain a composite anode material, carbon nanowalls (CNW) have been synthesized via CVD and combined with Si nanoparticles: the CNW outer layer proved to be able to protect Si beneath. In a view of green transition, rice husk has been used as a C source to produce carbon aerogels (CAs) and carbon dots (CDs). First, a synthetic process has been developed to obtain the nanostructures, whose properties as electrode materials have been evaluated both in supercapacitors and lithium-ion batteries. The reported results show the efficacy of RH derivatives as resistant cost effective alternatives to currently available materials in both devices. Prior to electrochemical testing, detailed characterization of all the abovementioned materials have been performed by means of SEM, EDS, AFM; XRD; Raman Spectroscopy, X ray Tomography and BET analysis. Besides routinary characterization, preliminary tests with AFM on electrodes have been conducted aiming at the optimization of our system to perform in operando electrochemical AFM.