Transfer of Vertical Graphene Nanosheets onto Flexible Substrates towards Supercapacitor Application

Vertical graphene nanosheets (VGNs) are the material of choice for next-generation electronic device applications. The growing demand for flexible devices in electronic industry brings in restriction on growth temperature of the material of interest. However, VGNs with better structural quality is usually achieved at high growth temperatures. The difficulty associated with the direct growth on flexible substrates can overcome by adopting an effective strategy of transferring the well grown VGNs onto arbitrary flexible substrates through soft chemistry route. Hence, we demonstrated a simple, inexpensive and scalable technique for the transfer of VGNs onto arbitrary substrates without disrupting its morphology and structural properties. After transfer, the morphology, chemical structure and electronic properties are analyzed by scanning electron microscopy, Raman spectroscopy and four probe resistive methods, respectively. Associated characterization investigation indicates the retention of morphological, structural and electrical properties of transferred VGNs compared to as-grown one. Furthermore the storage capacity of the VGNs transferred onto flexible substrates is also examined. A very lower sheet resistance of 0.67 kOhm/sq. and excellent supercapacitance of 158 micro-Farrad/cm2 with 91.4% retention after 2000 cycles confirms the great prospective of this damage-free transfer approach of VGNs for flexible nanoelectronic device application

Nanoparticle-enhanced Multifunctional Nanocarbons- Recent Advances on Electrochemical Energy Storage Applications

As renewable energy is becoming a crucial energy source to meet the global demand, electrochemical energy storage devices become indispensable for efficient energy storage and reliable supply. The electrode material is the key factor determining the energy storage capacity and the power delivery of the devices. Carbon-based materials, specifically graphite, activated carbons etc, are extensively used as electrodes, yet their low energy densities impede the development of advanced energy storage materials. Decoration by nanoparticles of metals, metal oxides, nitrides, carbides, phosphides, chalcogenides and bimetallic components is one of the most promising and easy-to-implement strategies to significantly enhance the structural and electronic properties, pore refinement, charge storage and charge-transfer kinetics of both pristine and doped carbon structures, thereby making their performance promising for next-generation energy storage devices. Structuring the materials at nanoscale is another probable route for better rate performance and charge-transfer kinetics. This review covers the state-of-art nanoparticle decorated nanocarbons (NCs) as materials for battery anode, metal-ion capacitor anode and supercapacitor electrode. A critical analysis of the elemental composition, structure, associated physico-chemical properties and performance relationships of nanoparticle-decorated NC electrodes is provided as well to inform the future development of the next-generation advanced energy storage materials and devices