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 LiNiO 2 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.