Electrochemical Kinetics and Cycle Stability Improvement with Nb Doping for Lithium-Rich Layered Oxides

Abstract

Lithium-rich layered oxide materials are extremely important for improving the energy density of lithium-ion batteries. However, the electrochemical kinetics and cycle stability of these materials are still not good enough for further industrial application. Here, the effects of Nb doping on the crystalline structure, surface chemistry, cycle stability, and electrochemical kinetics of Li1.13Mn0.52Ni0.26Co0.10O2 are studied. Results show that Nb doping can significantly promote the cycle stability and electrochemical kinetics of Li1.13Mn0.52Ni0.26Co0.10O2. After 200 cycles, the discharge capacity retention increases from 59.2% (pristine material) to 78.8% (1% Nb element doping) with obvious enhanced rate performance. Via X-ray diffraction, scanning electron microscope, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and galvanostatic intermittent titration analysis, it is confirmed that Nb element has been successfully doped into the bulk of Li1.13Mn0.52Ni0.26Co0.10O2. Doping sites of Nb element in structure and influence on lithium migration has also been studied by the Rietveld refinement and first principle theoretical calculation methods. Doped Nb element efficiently changes the lattice parameters, inhibits the resistance rise, accelerates lithium ion diffusion, and finally promotes the cycle stability, and electrochemical kinetics of Li1.13Mn0.52Ni0.26Co0.10O2.

3D Cube‐Maze‐Like Li‐Rich Layered Cathodes Assembled from 2D Porous Nanosheets for Enhanced Cycle Stability and Rate Capability of Lithium‐Ion Batteries

“…To further reveal the microstructure of SHC‐LMNCO, HRTEM images were analyzed, as shown in Figure e (Region 1 in Figure d) and Figure f (Region 2 in Figure d). Figure e exhibits a lattice spacing of 0.42 nm corresponding to the (020) plane of Li 2 MnO 3 with C/2m symmetry . The related fast Fourier transform (FFT) pattern (Figure g) represents a superposition of hexagonal symmetry of LiMO 2 phase and monoclinic C/2m symmetry of Li 2 MnO 3 phase which reflect a typical lithium/transition‐metal cation ordering in the transition metal layers along c axis of rhombohedral system (parallel to (100), (010), or (110) planes) .…”

“…The atomic ratio of Mn, Ni, Co detected from the EDS spectra (inset of Figure 2d) is almost identical to the designed value of 0.54:0.13:0.13, in consistent with the ICP-OES test (Table S1, Figure 2d). [39] The related fast Fourier transform (FFT) pattern ( Figure 2g) represents a superposition of hexagonal R3m symmetry of LiMO 2 phase and monoclinic C/2m symmetry of Li 2 MnO 3 phase which reflect a typical lithium/transition-metal cation ordering in the transition metal layers along c axis of rhombohedral system (parallel to (100), (010), or (110) planes). [39] The related fast Fourier transform (FFT) pattern ( Figure 2g) represents a superposition of hexagonal R3m symmetry of LiMO 2 phase and monoclinic C/2m symmetry of Li 2 MnO 3 phase which reflect a typical lithium/transition-metal cation ordering in the transition metal layers along c axis of rhombohedral system (parallel to (100), (010), or (110) planes).…”

Composite Nanostructure Construction on the Grain Surface of Li‐Rich Layered Oxides

“…Many strategies have been proposed to adjust the structures of LLOs to overcome the above drawbacks, including the local-structure control, [8] elemental doping, [12,13] crystal domain design, [7] surface modification, [14,15] and their combinations. [16] Among them, the construction of protective surface structures is effective to suppress side reactions, improve the structural stability, and promote the Li + diffusions across interface.…”

Analysis of Charge Storage Behavior in Redox‐electrolyte Based Battery‐like‐systems: A Case Study on Zr‐doped Ceria

“…The lower R ct value in the case in 2 M KOH denotes a faster rate of charge transfer. R ct value is independent of the frequency and inversely proportional to the rate of the reaction . The quasi‐reversibility of the reaction in the presence of redox additive (as confirmed from the CV) can be assigned to the relatively poor rate of the reaction and hence the higher value of R ct .…”

“…R ct value is independent of the frequency and inversely proportional to the rate of the reaction. [39] The quasi-reversibility of the reaction in the presence of redox additive (as confirmed from the CV) can be assigned to the relatively poor rate of the reaction and hence the higher value of R ct . The change in conductivity after the addition of redox couple in the electrolyte is clear from the equivalent circuit model study.…”