ADVANCES IN ELECTRODE MATERIALS RESEARCH

The technologies of primary (non-rechargeable) and secondary (rechargeable) lithium batteries have been developed in parallel to the developments in the microelectronics industry for about 20 years. The lithium batteries can be the lightest and most compact power sources when they are intended for portable equipment such as watches, calculators, cameras, cordless telephones, computers, and so on. During the past 10 years, the worldwide "green revolution" has requested a new, clear, and noiseless system of energy storage for replacing petrol. Rechargeable lithium batteries as high power and high energy density devices can also meet the requirements of clear and noiseless energy source, especially in the development of electric vehicles. Consequently, rechargeable lithium batteries with high power and long-life cycles have been very attractive to research groups all over the world. Thermodynamically, an electrochemical e.m.f, system is generated if an dectrolyte is sandwiched between two electrode materials with different chemical potentials. Electrodynamically, if a constant supply of ions can be maintained and transported through the electrolyte, this system will deliver current when connected across a load circuit. In the beginning of the research on rechargeable lithium batteries, a simple effect system has been studied. As a Li intercalation compound consists of a host (H) matrix into/from which x guest ions Li + may be inserted/extracted reversibly without a rearrangement of the host structure, a simple lithium battery may be represented as: