Regulating Ni 3d-O 2p Orbital Interaction with Position-Isomer Organic Lithiation Additive for High-Voltage LiNi_0.8Co_0.1Mn_0.1O₂ Cathode

High-voltage nickel-rich layered oxide cathodes have attracted much attention due to their high capacity and elevated voltage plateau. However, the intrinsic Ni 3d-O 2p orbital overlapping promotes lattice oxygen release during the Ni valence transition, thereby accelerating structural degradation and interfacial parasitic reactions. Herein, we found that the position-isomer slurry additive lithium 2-thiopheneboron (2LTB) suppresses Ni-O orbital overlap by enhancing the coordination of its Li, B, O, and S atoms with Ni and O in the cathode lattice, thereby stabilizing lattice oxygen at both the initial and deep discharge states. Electroactive 2LTB can form a thin and robust cathode electrolyte interface (CEI) that enhances Li⁺ diffusion dynamics while alleviating transition metal dissolution, irreversible phase transformation, gas evolution and electrolyte invasion under high voltage. Consequently, LiNi_0.8Co_0.1Mn_0.1O₂||Li cells with 1.5 wt.% 2LTB addition exhibits exceptional cycling performances, retaining 82.92% capacity retention after 450 cycles at 1 C and 76.09% after 800 cycles at 5 C under 4.5 V. A 1000-mAh LiNi_0.8Co_0.1Mn_0.1O₂-2LTB||graphite pouch cell maintains 81.34% capacity retention after 700 cycles. Our findings establish a versatile framework for leveraging lithiation reagents to regulate orbital interactions, providing both mechanistic insights and practical guidance for the development of high-voltage lithium-ion batteries.