Due to its unique features, laser-induced graphene (LIG) can be considered as disruptive technology for creating a few-layer graphene-based film that received much attention in the field of flexible electronics. Among all, energy storage, catalysis, sensing, and separation are the main applications that have been investigated in recent years with large improvements in the respective device performance. In particular, miniaturized supercapacitor—usually called a micro-supercapacitor (μSC)—is the most investigated field in which LIG can strongly provide outstanding results concerning the state of the art simplification of the fabrication procedure and intrinsically allowing the flexibility of the device. However, many open points still limit the possible full exploitation of this technology in the energy storage sector. This paper provides a concise overview of the LIG application in μSCs suggesting where the community should direct efforts to enhance the results together with associated challenges.

Renewable energy-based technologies and increasing IoT (Internet of Things) objects population necessarily require proper energy storage devices to exist. In the view of customized and portable devices, Additive Manufacturing (AM) techniques offer the possibility to fabricate 2D to 3D features for functional applications. Among the different AM techniques extensively explored to produce energy storage devices, direct ink writing is one of the most investigated, despite the poor achievable resolution. Herein, we present the development and characterization of an innovative resin which can be employed in a micrometric precision stereolithography (SL) 3D printing process for the fabrication of a supercapacitor (SC). Poly(3,4-ethylenedioxythiophene) (PEDOT), a conductive polymer, was mixed with poly(ethylene glycol) diacrylate (PEGDA), to get a printable and UV curable conductive composite material. The 3D printed electrodes were electrically and electrochemically investigated in an interdigitated device architecture. The electrical conductivity of the resin falls within the range of conductive polymers with 200 mS/cm and the 0.68 µWh/cm² printed device energy density falls within the literature range.

Titanium dioxide nanotubes (TiO₂ NTs) have been widely investigated in the past 20 years due to a variety of possible applications of this material. Indeed, their high surface area and tunable morphology can easily implement key features of TiO₂, such as its biocompatibility and photo‐ and electrocatalytic properties. This combination makes TiO₂ NTs perfect candidates for multifunctional applications ranging from biomedical application to sensing and energy devices. Herein, we present TiO₂ NTs grown by anodic oxidation on top of a titanium foil in an ethylene glycol‐based electrolyte with NH₄F. The as‐grown amorphous nanotubes were then subjected to annealing in a reducing atmosphere at different temperatures while maintaining their amorphicity. The morphological, physicochemical, and electronic properties were then thoroughly evaluated to assess their use in different fields, from energy storage devices to photo‐catalytical applications.

On the path toward independence from fossil fuels, solar energy is the most promising solution, but it needs a robust and reliable storage system to face its intrinsic fluctuations due to location, day cycle, and weather. The integration between energy harvesting and storage (H&S) technologies is a must toward clean energy production, and it becomes even more appealing considering the possibility of producing electricity not only from direct sunlight but also from diffuse light and indoor illumination. Herein, a dye‐sensitized solar module (DSSM) developed to harvest indoor illumination and directly store it into an electrical double‐layer capacitor (EDLC) is presented. Five series‐connected dye‐sensitized solar cells are fabricated on the same substrate and the module is integrated with a high‐voltage EDLC. The integrated device is characterized under indoor light sources such as light emitting diodes and fluorescent lamps. The results show one of the highest efficiencies ever reported for a high‐voltage DSSM under indoor illumination (16.27%), the largest voltage window ever reported for an indoor H&S device based on DSSM and EDLC—up to 3 V—and an overall photoelectric conversion and storage efficiency of 9.73% under indoor illumination.

In the last decades, the use of biochar has been receiving increasing attention for the development of electrochemical energy storage devices. In this work, the waste hazelnut shell biomass, a low cost and abundant agriculture residue within our territory, was valorized as feedstock for the synthesis of alkali-derived activated carbons, which were properly characterized and electrochemically tested, in the perspective of their use as new electrode material in energy storage applications. Two activated carbons have been identified as promising materials for this application and their electrochemical performances were further improved by including a doping step with copper (I) oxide, achieving the best specific capacitance of 123 F/g. Moreover, one of the two most promising activated carbons was tested in an EDLC symmetric device outperforming, at low power rates, reference materials in terms of specific energy density, reaching the value up to 40 Wh/kg, due to its remarkable specific capacitance of 55 F/g. In summary, this work proposes a sustainable and low energy demanding approach to transform waste biomasses into high value activated carbon materials for energy storage applications. The strategy not only promotes the reuse and valorization of hazelnut shell waste biomass, but it also supports a circular model with promising environmental and economic advantages.