Kinetic characteristics up to 4.8 V of layered LiNi1/3Co1/3Mn1/3O2 cathode materials for high voltage lithium-ion batteries

Abstract

Understanding the structure properties in deep delithiated states and electrochemical kinetics in the high potential window of LiNi1/3Co1/3Mn1/3O2 (NCM) cathode materials is essential to advance their performance in rechargeable lithiumion batteries for 5 V chemistry. Here we report a layered single-phase NCM showing great structural reversibility and without H3 phase formation when charged up to 4.8 V at least for 5 cycles. However, the poor cluster scale conductivity results in inactive material in thick electrode during cycling, approximately 10% (w/w), may corresponding to the reduced capacity respective to thin electrode. The Co 3+ /Co 4+ redox peaks are found clear and stable for cycles, lying between 4.5~5.0 V. That is tightly correlated to the fast Li-ion kinetic, i.e., the electrochemical behaviour of the NCM material is not limited by Li + diffusion but behaving like in a thin layer. That is very different from previously reports on charge transfer mechanisms of cathode materials for lithium-ion batteries.

Peroxo Species Formed in the Bulk of Silicate Cathodes

“…Here the orthorhombic lattice is used to track the structural evolution. As shown by the blue dots labelled as Orth-1 phase in Figure 4a and 4b,u pt op attern #4 0, which corresponds to % 0.65 Li + extraction with very little oxygen oxidation, the reflections of Orth-1 phase shift only slightly,with the lattice changing slightly and smoothly,c orresponding to av ery flat charging plateau, typically associated with cationic redox, i.e., Co 2+/ Co 3+ .T he intensity is reduced significantly for the highindexed reflections such as 220 and 260, but the intensity reduction is small for the low-indexed reflections,c .f.F igure S10, suggesting ad isruption of structural details on the long-range correlation length even occurring at the early delithiation stage.T his behavior is different from the continuous solid-solution reaction in layered oxide Li(NiCoMn) 1/ 3 O 2 , [25] and the abrupt two-phase reaction in LiFePO 4 . [27] In the ensuing delithiation, as et of new reflections stem from another orthorhombic phase Orth-2, shown by the green dots in Figure 4a and b.…”

Research Progress on the Surface of High-Nickel Nickel–Cobalt–Manganese Ternary Cathode Materials: A Mini Review

“…Cation mixing shifts the hierarchical R-3m space group to the tightly packed spinel Fm-3m space group. This tight structure leads to shorter ion spacing and larger interactions, making Li + diffusion difficult (Zhang et al, 2017). Studies have suggested that structural changes occur on the surface of high nickel layered oxides Liu et al, 2020).…”

Application of Operando X-ray Diffractometry in Various Aspects of the Investigations of Lithium/Sodium-Ion Batteries

“…During charge, Li ions are constantly removed from the LiMO 2 structure, leading to the changes of lattice parameters. In general, the lattice parameter c expands first and then contracts, often to a value smaller than that of the pristine state at high voltage due to the nearly empty Li layer [159][160][161]; this may cause the structure collapse in c-axis direction leading to the irreversible damage of the structure and capacity fade. To solve this problem, studies were devoted to discover and design new materials aimed at reducing the c variation during cycling to achieve the high-capacity retention and long cycle life.…”