Carbon/Li4Ti5O12 Hybrid Composite Nanotubes for Battery-Supercapacitor Hybrid Energy Storage Devices

In these days, it is generally accepted that various types of electrical vehicles will replace the present fossil fuel-powered vehicles due to increased concern on the environmental issues, such as wrenching climatic changes, resources depletion, etc. Lithium ion rechargeable batteries (LIBs) and supercapacitors are one of the most promising candidates for energy storage system for electrical vehicles. However, the current LIBs, which have been used in hybrid electrical vehicles or light electrical vehicles, cannot be adopted on the full electrical vehicles or heavy electrical vehicles due to low power efficiency. In the case of supercapacitor, electrochemical performance of energy density is lower than required value in electrical vehicle. Therefore, there is a heavy demand to develop the new concept of energy storage device for electrical vehicle with high performance, which is high energy density at high power density. Hybrid capacitor using asymmetric electrode system with organic electrolyte is one of the most available candidate energy storage devices. We tried herein to connect the gap between the LIBs and supercapacitor with hybrid energy storage device, biz. ‘BatCap’. We synthesized the Carbon/Li4Ti5O12 hybrid composite nanotubes (C/LTO-HCN) as for an anode of hybrid energy storage device via electrospinning method followed by hydrothermal reaction and heat treatment. The prepared hybrid composite samples were characterized by X-ray diffractometry, field emission scanning electron microscopy (in Fig. 1.), and high resolution transmission electron microscopy. The electrochemical performance of the hybrid composites was examined with a galvanostatic cell cycler at variable charge/discharge rates. Also, supercapacitor performance as a negative electrode of asymmetric electrode system was tested with activated carbon as a positive electrode.