Carbon coating of electrode materials for lithium-ion batteries

Lithium-ion batteries have become one of the most popular energy sources for portable devices, cordless tools, electric vehicles and so on. Their operating parameters are mostly determined by the properties of the anode material and, to a greater extent, the cathode material. Even the most promising electrode materials have disadvantages, such as large changes in the unit cell volume during the charge–discharge cycles, resulting in the electrode disintegration and capacity fading or low ionic or electronic conductivities. To overcome these shortcomings (destruction of materials or slow lithium diffusion), similar approaches are used, including the use of nanosize materials and the formation of composite materials with various conductive additives, the most popular of which is carbon. A small particle size causes less damage and minimises the diffusion path length, and carbon behaves as a buffer, thereby eliminating volume changes and providing a more stable contact between particles. Moreover, carbon coating of nanoparticles provides fast lithium diffusion along the interfaces. In this review, the authors summarised the recent research progress on carbon composites used in lithium-ion batteries. The theoretical foundations of electrochemical processes and some typical examples of the practical application of such composites are also outlined.