Positive electrode: active material, conductive agent, solvent, binder, and matrix. It's the electrode that gains electrons from the external circuit during battery discharge, at which point a reduction reaction occurs. It's typically the electrode with the highest potential. Examples include lithium cobalt oxide and lithium manganese oxide electrodes in lithium-ion batteries. Positive electrode materials have the largest market capacity and highest added value in lithium-ion batteries, accounting for approximately 30% of the battery cost, with gross profit margins ranging from 15% to over 70%.
Negative electrode: active material (graphite, MCMB, CMS), binder, solvent, and matrix. It's the electrode that supplies electrons to the external circuit during battery discharge, during which time oxidation occurs. It's typically the electrode with the lowest potential; graphite electrodes are used in lithium-ion batteries. Negative electrode materials account for a relatively small proportion of the cost of lithium batteries; important types include carbon-based and non-carbon-based negative electrode materials.
Separator: A separator is a device placed between two electrodes to isolate them, preventing direct contact between the active materials on the electrodes and thus avoiding short circuits inside the battery. However, the separator still needs to allow charged ions to pass through to form a pathway. Commercially available separator materials are mainly polyolefin separators, primarily made of polyethylene (PE) and polypropylene (PP). PE products are mainly produced using wet processes, while PP products are mainly produced using dry processes.
Electrolyte: The key to lithium-ion battery electrolyte materials lies in high safety and high environmental adaptability. Important developments will focus on: new solvents (widening the operating temperature range), ionic liquids, new lithium salts (improving environmental adaptability), and additives (flame retardants, redox shuttles, protecting the positive and negative electrode films, etc.).
Battery casings are divided into steel casings (rarely used for square batteries), aluminum casings, nickel-plated iron casings (used for cylindrical batteries), aluminum-plastic film (soft packaging), etc., as well as battery caps, which are also the positive and negative terminals of the battery.
