Molecular design through d-orbital induced electron redistribution tailors Li⁺coordination and cathode interfacial chemistry towards stable ultra-rich nickel Li batteries

Weakly solvation chemistry is an effective approach to stabilize LiNi_xCo_yMn_1-x-yO₂ (x ≥ 0.8) cathode for high energy density lithium-ion batteries (LIBs). Herein, we propose a d-orbital-induced electron redistribution-tailored solvation strategy that not only weakens Li⁺coordination and promotes anion-involved solvation, but also leverages coordination groups to actively participate in interfacial reactions, thereby forming multiphase hybrid cathode electrolyte interphase (CEI) to enhance LiNi_0.98Co_0.02O₂ battery performance. This strategy originates sulfur (S) atom utilizes its empty 3d-orbitals to induce the redistribution of the lone electron pair on the coordinated oxygen (O) atoms inside the 1,3-propylene sulfite (PSi), derived from ethylene carbonate (EC) after carbocycle regulation and S atom substitution. Computational and spectroscopic analyses confirm the reduced electron density on the sulfinyl oxygen (O_SO) of PSi. Sulfinyl oxygen groups together with anion form a multiphase stabilized CEI. Consequently, PSi-based electrolyte enhances the electrochemical performance of LiNi_0.98Co_0.02O₂ cells, delivering 83.67 % capacity retention over 300 cycles at 0.5 C and 158.44 mAh/g at 5 C in half cells, and 83.44 % capacity retention after 500 cycles in full cells, and 82.0 % capacity retention over 120 cycles in 1.68 Ah pouch cells. These results demonstrate a molecular-level electrolyte design principle for better interface chemistry and LIBs.