London Dispersion and Acido-Basicity of Ni-Rich Cathode Materials Using Inverse Gas Chromatography at Infinite...

The accelerating electrification of energy systems has positioned lithium-ion batteries (LIBs) as essential for high-efficiency storage. Yet, the surface energetics of Ni-rich layered cathodes remain poorly understood despite their critical role in interfacial stability. Here, inverse gas chromatography (IGC) at infinite dilution quantifies the surface free-energy components of two benchmark cathodes, NCM (LiNi_0.95Co_0.04Mn_0.01O₂) and NCMA (LiNi_0.95Co_0.02Mn_0.02Al_0.01O₂). NCM exhibits amphoteric behavior with dominant Lewis basicity (K_A = 1.48, K_D = 1.13), whereas Al incorporation in NCMA shifts the surface toward Lewis acidity (K_A = 1.64, K_D = 0.47), enhancing electrolyte affinity and suppressing interfacial degradation. Additionally, compared to NCM, our findings reveal reduced London dispersive surface energy (γ_S^L) values of NCMA, which reflect a decrease in the density of high-energy adsorption sites and an increased energetic uniformity of the surface, arising from aluminum-induced lattice tightening and surface densification. Full-cell tests at 45 °C confirm this energetic advantage: NCMA delivers 229.8 mAh g^-1 with 95% retention after 100 cycles, outperforming NCM (214.6 mAh g^-1, 92%). These results establish a direct correlation between surface energy descriptors and high-temperature durability, offering a quantitative framework for designing next-generation Ni-rich cathodes with superior interfacial and electrochemical stability.