No abstract

Structural energy storage systems offer both load bearing and electrochemical energy storage capabilities in a single multifunctional platform. They are emerging technologies for modern air and ground transportation vehicles, promising considerable mass and volume savings over traditional systems. To this end, carbon fiber reinforced composites have attracted interest for structural supercapacitors (SS), emanating principally from their similar laminate design. However, carbon fiber (CF) electrodes suffer from poor electrochemical storage performance. To tackle this deficiency, carbon fiber electrodes were modified with a 3D network of radially grown graphene nanoflakes (GNFs) to enhance their degree of graphitization and active surface area. We show that the GNF surface morphology offers an ∼9 times increase in specific capacitance (C sp) of CF structural supercapacitor. Moreover, chemical activation of the GNFs/CF hybrid electrodes by urea induces a further improvement in C sp by ∼14 times, while almost maintaining the elastic modulus of the control CF-based device. It has been established that the high specific capacitance stems from the highly electroactive edge-dominated nitrogen moieties and enhanced electrical conductivity induced by urea activation. Overall, the urea-activated hybrid electrodes offer an ∼12-fold increase in energy and power densities compared to CF control structural supercapacitor devices. These findings provide important knowledge for the design of next-generation multifunctional energy storage electrodes by highlighting the importance of interfacial nanoengineering.

Multiwall carbon nanotubes grown by plasma enhanced chemical vapour deposition were functionalized by H(2)O plasma treatment. Through a controlled functionalization process of the carbon nanotubes (CNTs) we were able to modify and tune their chemical reactivity, expanding the range of potential applications in the field of energy and environment. In particular, different oxygen groups were attached to the surfaces of the nanotubes (e.g. carboxyl, hydroxyl and carbonyl), which changed their physicochemical properties. In order to optimize the main operational parameters of the H(2)O plasma treatment, pressure and power, a Box-Wilson experimental design was adopted. Analysis of the morphology, electrochemical properties and functional groups attached to the surfaces of the CNTs allowed us to determine which treatment conditions were suitable for different applications. After water plasma treatment the specific capacitance of the nanotubes increased from 23 up to 68 F g(-1) at a scan rate of 10 mV s(-1).

The need for 2D vertical graphene nanosheets (VGNs) is driven by its great potential in diverse energy, electronics, and sensor applications, wherein many cases a low-temperature synthesis is preferred due to requirements of the manufacturing process. Unfortunately, most of today's known methods, including plasma, require either relatively high temperatures or high plasma powers. Herein, we report on a controllable synthesis of VGNs at a pushed down lowtemperature boundary for synthesis, the low temperatures (450 o C) and low plasma powers (30 W) using capacitively coupled plasma (CCP) driven by radio-frequency power at 13.56 MHz. The strategies implemented also include unrevealing the role of Nickel (Ni) catalyst thin film on the substrates (Si/Al). It was found that the Ni catalyst on Si/Al initiates the nucleation/growth of VGNs at 450 °C in comparison to the substrates without Ni catalyst.With increasing temperature, the graphene nanosheets become bigger in size, well-structured and well separated. The role of Ni catalysts is hence to boost the growth rate, density, and quality of the growing VGNs. Furthermore, this CCP method can be used to synthesize VGNs at the lowest temperatures possible so far on a variety of substrates and provide new opportunities in the practical application of VGNs.