Formation of carbon-metal oxide composites for lithium-ion battery anode materials

Abstract

As environmental issues such as abnormal climate and sea level rise due to global warming gradually emerge, environmentally friendly energy sources that can replace the existing fossil fuels are getting a lot of attention. Among them, electrochemical energy systems are attracting attention as the most promising alternatives, and lithium-ion batteries are being commercialized in various portable electrical devices including smartphones and laptops based on their high energy density. However, in order to utilize lithium-ion batteries in the advanced electronic devices such as electric vehicles, it is necessary to develop a battery having a high energy density. This dissertation concentrated on the study of utilizing metal oxides having a high theoretical capacity as an anode materials for lithium-ion battery to replace graphite, which is currently commercialized in lithium-ion battery as an anode material. In particular, a method of forming a composite with carbon material was developed to compensate the low electrical conductivity and structural instability of metal oxides. To increase the possibility of commercialization, the synthesis process of carbon-metal oxide composite was conducted under moderate experimental conditions. As a result, a composite having a structure in which a metal oxide and a carbon material can interact efficiently with each other was successfully synthesized, and we confirmed electrochemical operation of the composite as an anode material of lithium-ion battery. Higher energy storage capacity than graphite was achieved, and the improved electrochemical performance when a composite was formed with carbon was investigated.