Current state of high voltage olivine structured LiMPO₄ cathode materials for energy storage applications: A review

Continuous evolution of electrode materials still has not correspond today's energy storage system necessity and limits their application range. Numerous approaches are proposed to improve lithium ion batteries (LIBs) energy density including advancement of positive electrode materials. Olivine structured cathodes as LiCoPO₄ and LiNiPO₄ are excellent candidates due to their working potentials of exceeding 5.0 V vs. Li⁺/Li. Despite the efforts, these materials still have several intrinsic problems which demand various strategies to overcome. The paper systematically reviews the recent progress of these cathode materials. The approaches based on particle size manipulation via synthesis route variation and carbon addition, surface modification by coating with electron conducting carbon layer, and doping the structure with other metal ions were discussed and analyzed as the most impactful towards achieving competitive performance. Furthermore, the computational technique was discussed due to its importance in understanding and designing the materials from atomic to microscale levels. The potential applications of these cathodes in a new generation of all-solid-state Li-ion and aqueous batteries were described.