New Insight into the Role of Mn Doping on the Bulk Structure Stability and Interfacial Stability of Ni‐Rich Layered Oxide

Abstract

Nickel‐rich layered oxides have developed into appealing cathode materials for lithium‐ion batteries in recent years for the sake of high energy density and low cost, but they suffer from severe capacity deterioration during long‐term cycling. Herein, Mn‐doped nickel‐rich Li(Ni0.88Co0.09Al0.03)1‐δMnδO2 (δ=0, 0.01, 0.02) cathode materials with a nanoscale NixMn1−xO‐type pillar layer are synthesized using a facile high‐shear dry mixing and high‐temperature calcination process in this study. The as‐fabricated M0.01−NCA electrode with a NixMn1−xO‐type layer about 20 nm exhibits excellent cycle performance compared with the pristine in coin‐cells and in pouch cells (the long‐term cycle number is four times that of the pristine). Detailed investigation of the fading mechanism is performed by HRTEM, ex‐situ XRD, XPS et al. The enhanced performance is directly related to the synergetic effects of bulk inactive Mn4+ doping and the increased nanoscale NixMn1−xO‐type pillar layer. The Mn dopants stabilize the lattice structure thus decreasing the microcracks, and the pillar layer protects the cathode from parasitic reactions with electrolytes during long‐term cycling. This work gives a new insight into the role of Mn doping on the enhanced structure of nickel‐rich layered oxides.

Improving the Structure Stability of LiNi0.8Co0.15Al0.05O2 by Double Modification of Tantalum Surface Coating and Doping

“…Currently, surface coating − and ion doping − are the two main strategies to solve the above problems. Coating, as a common surface modification method, shows a positive effect on structural stability, side reaction inhibition, and the optimization of electrochemical stability.…”

Riveting Dislocation Motion: The Inspiring Role of Oxygen Vacancies in the Structural Stability of Ni-Rich Cathode Materials

“…The electrochemical performances of four samples (NC, V O -NC-1, V O -NC-2, and V O -NC-3) were measured using CR2025 coin cells, and the influence of elevated annealing temperature and time on electrochemical performances is explored as well (Figure ). Meanwhile, the performance is also compared with those reported in other literature studies as shown in Table S4. − Figure a shows the initial charge–discharge profiles of four samples, and the discharge capacities of modified cathode materials declined slightly at elevated annealing temperature and time. Although the NC sample obtains highest initial discharge capacity, its cycling performance is inferior as shown in Figure b, exhibiting only 155.3 mAh·g –1 (74.31% capacity retention) after 100 cycles at 0.2 C rate.…”

Enhancing the Electrochemical Performance of Ni-Rich LiNi0.88Co0.09Al0.03O2 Cathodes through Tungsten-Doping for Lithium-Ion Batteries

“…Recently, researchers have been attempting to improve the structural stability of nickel-rich cathodes via replacing transition metals with atoms of different elements. According to reports, various atoms (Na, Al, Ti, Mn, Y, Zr, Gd, F, and B) have been used to dope the nickel-rich layered cathode materials, which led to a great improvement in the electrochemical performance of the materials [10,13,19,[32][33][34][35][36]. Furthermore, Sun et al have demonstrated that W-doping can surmount the problem in LiNiO 2 with inherent structure instability and significantly improve its cycle performance and thermal properties without reducing its capacity [37].…”