Investigation of Li4Ti5O12 As a High Power Anode Material in Li-Ion Capacitor (LIC),

Abstract

Li-ion capacitor (LIC) technology is an advanced energy storage device that helps bridge the massive gap between Li-ion batteries (LIBs) and electric double-layer capacitor (EDLC), by incorporating the inherent advantages of both devices. It uses a LIB material as an anode (e.g. hard carbon or graphite) and EDLC (e.g. activated carbon) as a cathode to improve the energy density, power density, and cycle life. However, there are some applications that need an extremely fast rate of charge and discharge (high rate performance) which the present LIB electrode material used in LIC cannot provide. This is due to various limitations of the LIB electrode material which are; structural damage of the material during high rate performance, the safety of the material, and the cyclability. Lithium titanate oxide (Li4Ti5O12) is a material that can satisfy the requirements needed in high rate performance. This is because of its zero-strain insertion feature, very high safety, high efficiency, and excellent cyclability. However, it has an inherent problem of low electronic conductivity and poor ion diffusion. In order to address this issues, various approaches have been carried out by many researchers and it includes nano-structuring of the particle size to improve Li+ ion diffusion, surface coating with carbon, composting and many more. In this work, investigation of Li4Ti5O12 as an anode material in LIC is done by using one synthesis method (sol-gel) to synthesize Li4Ti5O12 of different particle sizes. The effect of different particle sizes of the synthesized Li4Ti5O12 on its performance as an anode in LIC is studied in terms of energy density, power density, efficiency, and cycle life. Cathode to anode ratio effect in LIC performance is also carried out. Also, the study of different carbon coating thicknesses on the Li4Ti5O12 particles and how it affects its performance will also be carried out.