Lithium Iron Orthosilicate Cathode: Progress and Perspectives

The pursuit of cathodes with a high capacity is remarkably driven by the ever increasing demand of high-energy lithium ion batteries in electronics and transportation. In this regard, polyanionic lithium iron orthosilicate (Li 2 FeSiO 4 ) offers a promising opportunity because it affords a high theoretical capacity of 331 mAh g –1 . However, such a high theoretical capacity of Li 2 FeSiO 4 has frequently been compromised in practice because of the extremely low electronic and ionic conductivity. To address this issue, material engineering strategies to boost the Li storage kinetics in Li 2 FeSiO 4 have proven indispensable. In this Perspective, we will briefly present the structural characteristics, intrinsic physicochemical properties, and electrochemical behavior of Li 2 FeSiO 4 . We particularly focus on recent materials engineering of silicates, which is implemented mainly through advanced synthetic techniques and elaborate controls. This Perspective highlights the importance of integrating theoretical analysis into experimental implementation to further advance the Li 2 FeSiO 4 materials.