The demand for energy increases steadily with time due to population and economic growth and advances in lifestyle. As energy usage increases, concerns about environmental pollution associated with the use of fossil fuel are becoming serious. Li ion batteries have become prominent over the past two decades, particularly for portable electronics, as they offer much higher energy density than other rechargeable systems. The current Li ion technology is based on insertion-compound anode and cathode materials, which limit their charge-storage capacity and energy density. A further increase in energy density needs to be achieved through an increase in the charge-storage capacity of the anode and cathode materials or an increase in the cell voltage or both. The lithium ions produced move to the positive electrode through the electrolyte internally while the electrons travel to the positive electrode through the external electrical circuit, and thereby an electrical current is generated.