Dual-shell silicate and alumina coating for long lasting and high capacity lithium ion batteries

Direct Imaging of the Structural and Morphological Evolution of Epitaxial LiCoO2 Films during Charge and Overcharge

“…Layered LiCoO 2 (LCO) has been studied extensively as a cathode material in lithium-ion batteries (LIBs) because of its excellent reversibility and high theoretical capacity. − However, in realistic applications, only ∼140 mAh g –1 discharge capacity is realized corresponding to a cutoff voltage of ∼4.2 V, , which is not sufficient to meet the growing demand for high energy density LIBs, particularly for use in electric vehicles (EVs). Although charging LCO to a high voltage is a possible method to boost the energy density by extracting more Li ions from the structure, − over-delithiation leads to serious capacity attenuation during cycling. This can be attributed to two aspects: the detrimental interfacial side reactions resulting from irreversible phase transformations and nonuniform stresses induced by the inhomogeneous Li distribution during lithiation/delithiation in LCO, which ultimately leads to structural damage and diffusion blockage. − Different LCO failure mechanisms, such as interfacial redox reactions , and oxygen release, , have been proposed to study high-voltage applications.…”