The Role of Intentionally Introduced Defects on Electrode Materials for Alkali-Ion Batteries

Simple defect modification is a powerful means to improve material intercalation capabilities. It has received considerable interest lately as it can directly alter both the chemical and structural characteristics; techniques of note include cationic disordering, amorphization, doping, partial cation reduction, and manipulation of intrinsic defects. Defects can reduce the stress and the electrostatic repulsion between adjacent oxygen layers, which can directly alter the migration energy and diffusion barriers the alkali ion must overcome during intercalation. Complementary to experimental observations, theoretical predictions are paramount to developing a detailed understanding of material-defect chemistry. This focus review aims to demonstrate that the optimized design of stable intercalation compounds could lead to substantial improvements in energy-storage applications by overcoming intrinsic limitations.