The positive and negative electrode materials are critical components that determine a battery's performance; differences in these materials lead to significant variations in voltage, capacity, cycle life, safety, and application scope across different battery types. During operation, electrochemical reactions occur between the positive and negative electrodes, generating an electric current through the movement of electrons and converting chemical energy into electrical energy. Typically, the negative electrode releases electrons (undergoing oxidation), while the positive electrode accepts electrons (undergoing reduction). The choice of these materials directly impacts the battery's energy density, charge-discharge efficiency, and service life.
Lead-acid batteries utilize lead dioxide (PbO₂) for the positive electrode and spongy lead (Pb) for the negative electrode, with a sulfuric acid solution serving as the electrolyte. During discharge, both electrode materials react chemically with the sulfuric acid to produce an electric current. Characterized by mature technology, low cost, and high reliability, lead-acid batteries have long been used in automotive starter systems, UPS backup power supplies, telecommunications base stations, and energy storage systems. However, the high density of lead results in relatively low energy density and significant battery weight.
Lithium-ion batteries employ a wide variety of positive and negative electrode materials and currently represent the most widely used battery type. Common positive electrode materials include lithium iron phosphate (LiFePO₄), ternary materials (such as NCM-nickel-cobalt-manganese-or NCA-nickel-cobalt-aluminum), and lithium cobalt oxide (LiCoO₂); negative electrodes typically use graphite, though some newer batteries incorporate silicon-based materials to enhance energy storage capacity. These batteries operate through the intercalation and de-intercalation of lithium ions between the positive and negative electrodes. Offering advantages such as high energy density, light weight, and long cycle life, they are extensively used in new energy vehicles, energy storage systems, electronic devices, and high-performance UPS power supplies.
Other battery types also utilize distinct positive and negative electrode materials. For instance, nickel-metal hydride (NiMH) batteries typically use nickel oxyhydroxide (NiOOH) for the positive electrode and a hydrogen-storage alloy for the negative electrode, while nickel-cadmium (NiCd) batteries use nickel oxyhydroxide for the positive electrode and cadmium for the negative electrode. As battery technology continues to evolve, new electrode materials-such as silicon-carbon composites, solid-state electrolytes, and materials for sodium-ion batteries-are increasingly being researched and implemented. In the future, optimizing the structures of cathode and anode materials will enable further improvements in battery capacity, safety, and cycle life, providing more reliable technical support for the development of new energy storage and smart power systems.