Synergistic Bulk‐Surface Modulation Stabilizing LiCoO 2 at 4.65 V via Zr‐Pillaring and In Situ Lattice‐Matching Engineering
Guanming Yang, Jianhang Cui, Bingwu Zhou, Xin Meng, Yun Zhao, Wenglam Wong, Yuqiong Kang, Hao Du, Xiaoyu Zhou, Jichang Liu, Jue Gong, Baohua Li, Jiajun Wang, Haiping XuABSTRACT
Lithium cobalt oxide (LiCoO 2 , LCO) is a critical cathode material for high‐energy‐density lithium‐ion batteries, yet its application above 4.55 V (vs. Li/Li + ) is severely limited by structural degradation via the O3→H1‐3 phase transition, lattice oxygen loss, and cobalt dissolution. Here, we report a synergistic bulk‐surface modification strategy combining Zr‐pillaring (LZCO) with in situ LiCoPO 4 coating (LZCO@P) to stabilize LCO at 4.65 V. Zr‐pillaring stabilizes the lattice and suppresses phase transition by expanding the O 2p‐Co 3d band gap, as suggested by density functional theory (DFT), to mitigate oxygen redox activity. Lattice‐matched interfacial engineering between LZCO and LiCoPO 4 coating results from interfacial P–O tetrahedral formation, which enhances mechanical adhesion and reduces oxygen surface reactivity of LZCO. Consequently, LZCO@P achieves 80.8% capacity retention after 1000 cycles at 1 C (3.5–4.65 V) and 91.2% after 1000 cycles at 3 C (3.5–4.65 V). A practical Li||LZCO@P pouch cell retains 92.3% capacity after 160 cycles at 1 C (3.0–4.6 V). The synergistic bulk‐surface modification strategy contributes through different mechanisms and comprehensively improves the cycling stability of LZCO@P at 4.65 V.