Chemomechanically Stable Ultrahigh-Ni Single-Crystalline Cathodes with Improved Oxygen Retention and Delayed Phase Degradations.

The pressing demand in electrical vehicle (EV) markets for high-energy-density lithium-ion batteries (LIBs) requires further increasing the Ni content in high-Ni and low-Co cathodes. However, the commercialization of high-Ni cathodes is hindered by their intrinsic chemomechanical instabilities and fast capacity fade. The emerging single-crystalline strategy offers a promising solution, yet the operation and degradation mechanism of single-crystalline cathodes remain elusive, especially in the extremely challenging ultrahigh-Ni (Ni > 90%) regime whereby the phase transformation, oxygen loss, and mechanical instability are exacerbated with increased Ni content.

Enabling multi-electron reaction of ε-VOPO to reach theoretical capacity for lithium-ion batteries.

By controlling the morphology and particle size of the epsilon polymorph of vanadyl phosphate, ε-VOPO4, it can fully reversibly intercalate two Li-ions and reach the theoretical capacity of 305 mA h g-1 over two voltage plateaus at about 4.0 and 2.5 V.

Can Multielectron Intercalation Reactions Be the Basis of Next Generation Batteries?

Intercalation compounds form the basis of essentially all lithium rechargeable batteries. They exhibit a wide range of electronic and crystallographic structures. The former varies from metallic conductors to excellent insulators.