Nano-assembly of two-dimensional titanium carbides (MXenes) for electrochemical energy storage

Abstract

Rapid economic development and growth worldwide has accelerated the use of energy sources, including fossil fuels such as coal, oil, and natural gas. However, imprudent energy consumption has adversely affected the Environment. In particular, the gradual increase in the amount of carbon dioxide (CO$_2$) emitted from anthropogenic activities has led to global warming. Hence, over the past 25 years, Li-ion batteries (LIBs) have been developed as alternate energy carriers. They play important roles in rechargeable portable electronic devices, hybrid electric vehicles, and electric vehicles, without emitting CO$_2$. Nevertheless, LIBs are not suitable for use in high-capacity applications because of their limited energy density

in addition, the raw materials used to fabricate their electrodes are both expensive and toxic. In order to overcome these limitations, lithium-ion batteries with improved energy density and theoretical capacity have been researched and developed. Lithium−sulfur (Li−S) batteries offer a greater theoretical energy density (2600 Wh kg$^{−1}$) and capacity (1672 mAh g$^{−1}$) than LIBs. Moreover, earth-abundant sulfur is both inexpensive and nontoxic. Recently, transition metal carbides/nitrides (MXenes), as one class among numerous two-dimensional (2D) materials, have been highlighted in various applications such as batteries, catalysts, transparent conducting coatings, sensors, and water purification systems. MXenes are considered as materials with strong future research prospects because of their appealing properties, which include (i) good flexibility, (ii) the ability to be fabricated in desired shapes, and (iii) high conductivity. In this dissertation, we showed the study of applying nano-assembly of two-dimensional metal carbide (MXenes) materials to lithium-sulfur batteries and lithium-ion batteries. The results in this study improved electrochemical performance in energy storage devices.