Enhancing surface‐to‐bulk stability of layered Co‐free Ni‐rich cathodes for long‐life Li‐ion batteries

Abstract

Layered Co‐free Ni‐rich cathodes are the most cost‐effective for high‐energy‐density Li‐ion batteries (LIBs), yet the structural instability and interfacial side reactions seriously hamper their commercial applications versus the Co‐contained counterpart. Herein, a synchronous Ge‐doping and Li4GeO4‐coating of the Co‐free Ni‐rich cathodes have been realized to tackle these limitations during high‐temperature lithiation of the corresponding hydroxide precursors. The nonmagnetic Ge4+ doping effectively relieves the magnetic frustration and the lattice oxygen loss with reduced cation mixing and gas emission. The Li‐ion conductive and anti‐erosive Li4GeO4 coatings contribute to enhance the surface chemistry stability and Li‐ion migration interface kinetics. Consequently, the resulting Co‐free Ni‐rich cathodes delivers a high reversable capacity of 223.3 mAh g−1 at 0.1 C and maintains 127.5 mAh g−1 even at 10C within 2.7–4.4 V. More impressively, it displays high‐capacity retention of 90.5% in coin‐type half‐cell after 150 cycles and 80.5% in pouch‐type full‐cell after 500 cycles at 3C, demonstrating a long‐term cycle life.

Enhanced Li-ion intercalation kinetics and lattice oxygen stability in single-crystalline Ni-rich Co-poor layered cathodes

“…1d), and its structural renement demonstrated that BA-NCM85 had an extremely low Li/Ni mixed value of 1.55%. 29,30 Furthermore, the Li/Ni cation disorder of B-NCM85 (1.83%) and A-NCM85 (2.26%) was much lower than that of pristine NCM85 (3.21%) (Fig. S6 †).…”

Operando Building of a Superior Interface Hybrid Film Enables Chemomechanically Durable Co-Free Ni-Rich Cathodes

“…The Ni 0.9 Mn 0.1 (OH) 2 precursors were prepared by a co-precipitation method in a batch reactor (10 L) under an argon atmosphere, which has been described in detail in our previous works. 10 The obtained Ni 0.9 Mn 0.1 (OH) 2 precursor was mixed with stoichiometric LiOH•H 2 O (molar ratio of lithium to transition metals = 1.02). The mixture was precalcined at 450 °C for 6 h followed by sintering at 770 °C for 13 h in a pure oxygen atmosphere to obtain the pristine LiNi 0.9 Mn 0.1 O 2 oxides (NM91).…”

“…There are two main methods available. One is to coat a layer of inorganic compounds on the cathodes as a physical barrier to prevent the erosion of the active materials by adverse components such as HF in the electrolyte. , However, its low ductility makes it easy to crack and fall off after long-term cycles owing to the repeated volumetric shrinkage and swelling of cathodes . The interfacial contact resistances among the cathode, coating layer, and CEI film also gradually increase, vastly worsening the rate performance.…”

“…10.1021/acsnano.4c04125. Details of simulations and calculations; SEM images, XRD patterns, EDS mappings, XPS spectra, modulus mappings, polarization values, EIS spectra, CV curves, charging/discharging curves, dQ/dV curves, and TEM images of NM91 and 2%TMSB-NM91; comparison of electrochemical performance between 2%TMSB-NM91 and previously reported LiNi 0.9 Mn 0.1 O 2 (PDF)…”

Atomic-level insights into the first cycle irreversible capacity loss of Ni-rich layered cathodes for Li-ion batteries

“…[24][25][26][27][28][29][30][31] Additionally, anion substitution, 32 partial nickel substitution in LiNiO 2 with various elements such as Mg, Mn, Cr, Fe, Co, Al, Ga, Zr, Ti, Sb, W, Mo, and F, has been explored. [33][34][35][36][37]50,51 Concurrent coating techniques, 38,39 surface-tobulk modications, 40,41 core/shell-type structure design, 42,43 and innovative recycling methodologies 44 for Ni-rich compounds also contribute to this growing eld. These developments have reignited interest across academia and industry, as most of these observations demonstrate improved cyclic stability and rate capability.…”