Positron quantum probe diagnosis at the cathode/graphite interface in a Co-free Ni-based cathode to optimize Li-ion mobility

Lithium-ion batteries (LIBs) are among the most promising power sources covering a wide range of applications by persistent de-bottlenecking the low electrical conductivity and Li-ion diffusivity of the cathode. This study proposes a cobalt-free, nickel oxide-based cathode, addressing the sustainable concerns associated with cobalt reduction or elimination. Coating the cathode micro-particles with carbon is a common approach for improving the electric conductivity and structural stability against cycling-induced degradation. Using positron annihilation lifetime spectroscopy (PALS) as a quantum probe of interfacial interactions, complemented by advanced density functional theory simulations, we investigated the role of carbon layer boosting the Li-ion mobility for fast charging. PALS results obtained in LiNiO2 reveal that the presence of filaments into the cathode grain microstructure, combined with the carbon capping layer, enhances positron mobility. Therefore, PALS can be used as a sensitive diagnostic tool, providing detailed insights for optimizing interfacial Li-ion dynamics to advance the development of fast-charging batteries for the future.