Enhanced Electrochemical Properties of Zr4+-doped Li1.20[Mn0.52Ni0.20Co0.08]O2 Cathode Material for Lithium-ion Battery at Elevated Temperature

Abstract

The typical co-precipitation method was adopted to synthesized the Li-excess Li1.20[Mn0.52−xZrxNi0.20Co0.08]O2 (x = 0, 0.01, 0.02, 0.03) series cathode materials. The influences of Zr4+ doping modification on the microstructure and micromorphology of Li1.20[Mn0.52Ni0.20Co0.08]O2 cathode materials were studied intensively by the combinations of XRD, SEM, LPS and XPS. Besides, after the doping modification with zirconium ions, Li1.20[Mn0.52Ni0.20Co0.08]O2 cathode demonstrated the lower cation mixing, superior cycling performance and higher rate capacities. Among the four cathode materials, the Li1.20[Mn0.50Zr0.02Ni0.20Co0.08]O2 exhibited the prime electrochemical properties with a capacity retention of 88.7% (201.0 mAh g−1) after 100 cycles at 45 °C and a discharge capacity of 114.7 mAh g−1 at 2 C rate. The EIS results showed that the Zr4+ doping modification can relieve the thickening of SEI films on the surface of cathode and accelerate the Li+ diffusion rate during the charge and discharge process.

A study of the effect of tungstate ions on the electrochromic properties of Ni(OH)2 films

“…NO 3 can be exchanged for other ions. We assume that exchange of nitrate for tungstate occurs, similar to intercalation that occurs with the cathode in lithium batteries [39,40]. Due to the larger size of 2 4 WO , a greater deformation occurs in the crystal lattice, resulting in the potential shift.…”

Understanding the Role of Dopant Metal Atoms on the Structural and Electronic Properties of Lithium-Rich Li1.2Ni0.2Mn0.6O2 Cathode Material for Lithium-Ion Batteries

“…Over the past years, many efforts have been made to overcome this issue, including surface passivation, , doping, − particle size reduction, , and nanomorphology. , Among them, the substantial substitution of the cation in LiMO 2 has been proven effective in improving the structural stability of LiMO 2 during the delithiation process. − Previously, Qiao et al partially substituted Mn 4+ with Sn 4+ in the Li­(Li 0.17 Ni 0.25 Mn 0.58 )­O 2 cathode and reported the enhanced electrochemical performance . Similarly, the substitution of Mo 6+ and Nb 5+ to Mn 4+ has improved the rate and cycling performance of the Li-rich cathode materials. , Feng et al reported that 2.5% doping of aliovalent Ti 4+ ions to Li + ions in the Li-layer exhibits a reversible capacity of >320 mAh g –1 , along with good rate performance .…”

Improving the Thermal Stability of NMC 622 Li-Ion Battery Cathodes through Doping During Coprecipitation

“…These NMC materials are usually produced in two major steps: coprecipitation and calcination. Coprecipitation is commercially achieved using continuous stirred tank reactors (CSTRs) starting with soluble transition metal salts. − Often hydroxide precursors are made by continuously adding specific ratios of ammonium hydroxide, sodium hydroxide, and transition metal solutions to the reactor at constant pH and temperature. ,,− During this process, it is possible to include a dopant by adding a soluble salt of the desired element to the transition metal solution. , The material is then rinsed, filtered, and dried before being mixed with a lithium source and calcined at high temperature to form the final structure. Dopants could also be added at this point in the reaction by mixing a precursor with a compound containing the desired element that decomposes during the heat treatment. ,,, However, this can result in gradients in the doping concentration, whereas coprecipitation typically will create a uniform distribution throughout the bulk.…”