Improving the Structure Stability of LiNi_0.8Co_0.15Al_0.05O₂ by Double Modification of Tantalum Surface Coating and Doping

Abstract

The structural instability of high-nickel materials severely limits their commercial applications. In this article, a one-step high-temperature solid-phase sintering method is applied to form a Ta2O5 protective layer on the surface of LiNi0.8Co0.15Al0.05O2 (NCA) with Ta5+ entering the lattice, which achieves the double-effect of coating and doping. The Ta2O5 protective coating can inhibit the side reaction between the electrode material and electrolyte, and Ta5+ doping can relieve the Li+/Ni2+ disorder ratio. These significantly enhance the structural stability of NCA. The obtained NCA-Ta2O5 displays an excellent capacity retention rate (94.46%, at 1C after 200 cycles), which is much better than that (60.97%) of the pristine NCA. The exploration of structural evolution reveals that NCA-Ta2O5 can maintain a good spherical structure without obvious cracks after 200 cycles at 1C, while the original NCA has a serious structural collapse. Besides, NCA-Ta2O5 presents outstanding discharge capacity (151.02 mAh g–1 vs NCA: 131.70 mAh g–1) at a high rate of 10C. This work provides ideas for improving the performance of high-nickel materials, which is of great significance to the optimization of the cathode material for lithium-ion batteries.

Enhanced Electrochemical Performance and Safety of LiNi0.88Co0.1Al0.02O2 by a Negative Thermal Expansion Material of Orthorhombic Al2(WO4)3

“…The main peaks of Al 2 (WO 4 ) 3 match well with the peaks of the standard spectrum of Al 2 (WO 4 ) 3 (PDF# 81-2415), which indicates that the as-obtained Al 2 (WO 4 ) 3 has a well-ordered orthorhombic structure. The diffraction peaks of AW0 and AW5 electrodes before cycles show no obvious difference, and both samples show a typical α-NaFeO 2 structure. , The Al 2 (WO 4 ) 3 with 5 wt % in AW5 does not influence the structure of NCA. The Al peaks on the spectra of the samples are from the Al foil substrates where active materials were loaded.…”

“…The diffraction peaks of AW0 and AW5 electrodes before cycles show no obvious difference, and both samples show a typical α-NaFeO 2 structure. 44,45 The Al 2 (WO 4 ) 3 with 5 wt % in AW5 does not influence the structure of NCA. The Al peaks on the spectra of the samples are from the Al foil substrates where active materials were loaded.…”

Stabilizing High-Voltage Cathodes via Ball-Mill Coating with Flame-Made Nanopowder Electrolytes

“…More importantly, the XRD peaks progressively shift toward higher angles with increasing amounts of Al 2 O 3 , LiAlO 2 , and LATSP NPs, as shown in the magnified (003) peaks at 18–19° 2θ, which indicates the lattice parameter decreases. The gradual decrease in the lattice parameter with increasing amounts of NPs can be attributed to the substitution of transition-metal ions by smaller Al 3+ (0.54 Å) or Ti 4+ (0.61 Å) ions . Therefore, ions in the NP layers probably partially diffuse into surfaces and perhaps the interiors of the LMNO particles during milling.…”

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

“…Currently, they are most often used in laptops, mobile phones, digital cameras, and other portable devices, as well as in electric and hybrid cars [1][2][3][4][5]. Among the commonly available LIB cathode materials, Ni-rich layered cathode materials, particularly LiNi x Co y TM 1−x−y O 2 , are believed to be the best choice of power sources for the current electric vehicles [6][7][8][9][10][11][12][13]. The LiNi 0.8 Co 0.15 Al 0.05 O 2 cathodes, for example, have been successfully applied to LIB to store electricity for Tesla electric vehicles, but it still has a cruising distance problem and insufficient cycle life [5,14,15].…”

“…Numerous strategies have been employed to strengthen the host structure by doping, coating, and establishing special architectures such as the core-shell model [9,13,27,30]. Atomic doping is widely considered to enjoy a promising development, with simple operation to significantly improve battery lifetime, rate capability, and structural integrity of nickel-rich cathode materials.…”