Core-Shell Amorphous FePO4 as Cathode Material for Lithium-Ion and Sodium-Ion Batteries

Amorphous FePO4 (AFP) is a promising cathode material for lithium-ion and sodium-ion batteries (LIBs & SIBs) due to its stability, high theoretical capacity, and cost-effective processing. However, challenges such as low electronic conductivity and volumetric changes seriously hinder its practical application. To overcome these hurdles, core-shell structure synthesis emerges as a useful solution. In this work, we for the first time made this comprehensive review on the progresses of core-shell amorphous FePO4 (CS-AFP). This review summarizes 1) various synthesis methods such as template method, microemulsion method, and other methods, 2) characterization techniques, and 3) their involvement in improving electrochemical performance in LIBs and SIBs. In terms of further understanding the underlying mechanisms of advancing electrochemical performance of CS-AFP, the future perspective on two main aspects were insighted: (i) in situ characterization and (ii) novel designs of materials and structure for CS-AFP.