The Basic Elements in Lithium-ion Batteries Electrodes, Electrolytes and Collectors

The Basic Elements in Lithium-ion Batteries Electrodes, Electrolytes and Collectors 

Unlike many other secondary batteries, lithium-ion batteries are not linked to a single electrochemical couple. In fact, any material which is able to reversibly accommodate lithium ions can be considered as an active material in a lithium-ion battery. Hence, this implies a great diversity of types of materials for the electrodes, each of which has different properties in terms of gravimetric and volumetric energies, nominal voltage, lifetime, safety, cost, etc. 

lithium-ion battery technology is lar from being fixed. Numerous university-based researchers and industrialists are working on ways to improve lithium batteries, which involves better awareness of the properties of each of the two electrodes, the electrolyte, current collectors and the interactions between them. The domain is so complex that there are research teams specializing in the study of positive electrodes, whereas others specialize solely in the study of negative electrodes. 

Ultimately, at present, there is no one electrode which is excellent for all the objectives sought for the best battery, because compromises must be sought. Thus, a very high specific energy is, as yet, still usually synonymous with a short lifetime. Also, better operational safety is obtained to the detriment of specific energy. 

This chapter looks at different electrodes that are used or are under investigation, taking an interest in their properties first positive electrodes, then negative electrodes, then electrolyte and finally current collectors. In order to work on an electrode, electrochemists often combine it with a counter-electrode made of metal lithium. They refer to this setup as a half celfi (although the cell is complete, with both of its electrodes), because it is assembled in a coin-cell-type casing, which is easy to use in the laboratory. 

---