Rational process design of cost-benefit prelithiation additive Li5FeO4 enables high-performance lithium-ion batteries

Li 5 FeO 4 (LFO), an ideal cathode prelithiation additive for lithium-ion batteries, has attracted significant interest because of its extremely high capacity, suitable voltage window, and environmental friendliness. However, the solid-phase synthesis process of LFO is not clear and suffers from the exorbitant cost of Li 2 O, making finding an alternative lithium source for improving cost-effectiveness in industrial production crucial. In this study, LFO materials were synthesized via a solid-phase sintering method involving two types of lithium sources. Utilizing in-situ X-ray diffraction and X-ray absorption fine structure spectroscopy, the evolution mechanism of solid-phase synthesis was elucidated. In particular, a low-temperature plateau was determined for the synthesis process employing LiOH as the lithium source. Compared with Li 2 O-derived O-LFO, the as-obtained prelithiation additive H-LFO achieved an ∼69.7% cost reduction with satisfactory initial charge capacity, energy density and cycling stability in industrial-scale applications. This work provides a practical solution for promoting prelithiation technology and reducing the preparation cost of prelithiation additives.