Cathode materials for lithium ion batteries prepared by sol-gel methods

Improving the preparation technology and electrochemical performance of cathode materials for lithium ion batteries is a current major focus of research and development in the areas of materials, power sources and chemistry. Sol-gel methods are promising candidates to prepare cathode materials owing to their evident advantages over traditional methods. In this paper, the latest progress on the preparation of cathode materials such as lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, vanadium oxides and other compounds by sol-gel methods is reviewed, and further directions are pointed out. The prepared products provide better electrochemical performance, including reversible capacity, cycling behavior and rate capability in comparison with those from traditional solid-state reactions. The main reasons are due to the following several factors: homogeneous mixing at the atomic or molecular level, lower synthesis temperature, shorter heating time, better crystallinity, uniform particle distribution and smaller particle size at the nanometer level. As a result, the structural stability of the cathode materials and lithium intercalation and deintercalation behavior are much improved. These methods can also be used to prepare novel types of cathode materials such as nanowires of LiCoO₂ and nanotubes of V₂O₅, which cannot be easily obtained by traditional methods. With further development and application of sol-gel methods, better and new cathode materials will become available and the advance of lithium ion batteries will be greatly promoted.