Understanding Lithium-ion Technology

To the average person, lithium-ion technology, at least until the last year or so, was represented by the black-box-like batteries in high-end consumer devices such as laptop computers. Mobile phone batteries use similar chemistry, although in that case the batteries are often lithium-polymer types that are frequently described as if they constitute an entirely different technology. The mystique of lithium-ion batteries even seems to extend to the industry lexicon, with cognoscenti talking about cathode and anode materials—words familiar from physics or chemistry courses at school but rarely used in the world of lead-acid batteries. Now, amid news stories about safety issues and consumer battery recalls we are seeing lithium-ion batteries being promoted for power tools, electric vehicles and also standby-power applications. New terminology is appearing, such as iron phosphate and lithium titanate, and nanotechnology is being incorporated into some designs. Confusion reigns, because all of these products fall into the same broad ‘lithium-ion’ category. This paper describes the various electrochemical couples that together form the lithium-ion family. The characteristics of the main couples will be described, particularly with respect to safety improvements and their potential operational tradeoffs. The aim of the paper is to provide a basic understanding of lithium-ion batteries and their potential for use in a variety of stationary applications.