The Effects of Reversibility of H2-H3 Phase Transition on Ni-Rich Layered Oxide Cathode for High-Energy Lithium-Ion Batteries

Abstract

Although LiNi 0.8 Co 0.1 Mn 0.1 O 2 is attracting increasing attention on account of its high specific capacity, the moderate cycle lifetime still hinders its large-scale commercialization applications. Herein, the Ti-doped LiNi 0.8 Co 0.1 Mn 0.1 O 2 compounds are successfully synthesized. The Li(Ni 0.8 Co 0.1 Mn 0.1 ) 0.99 Ti 0.01 O 2 sample exhibits the best electrochemical performance. Under the voltage range of 2.7 – 4.3 V, it maintains a reversible capacity of 151.01 mAh·g −1 with the capacity retention of 83.98% after 200 cycles at 1 C. Electrochemical impedance spectroscopy (EIS) and differential capacity profiles during prolonged cycling demonstrate that the Ti doping could enhance both the abilities of electronic transition and Li ion diffusion. More importantly, Ti doping can also improve the reversibility of the H2-H3 phase transitions during charge-discharge cycles, thus improving the electrochemical performance of Ni-rich cathodes.

Thin Film NCM Cathodes as Model Systems to Assess the Influence of Coating Layers on the Electrochemical Performance of Lithium Ion Batteries

“…the peak at 4 V can be attributed to an additional phase transition during oxidation of NCM811. The first transition from the hexagonal layered phase to a monoclinic one is located at around 3.8 V, while the second transition, from the monoclinic to a second hexagonal phase, occurs at around 4.0 V. [ 51 ] This behaviour is also found for NCM111 powder materials. [ 51 ] Several studies confirm that an ultrathin coating of the cathode material inhibits the additional phase transition at around 4.0 V, which is in good agreement with our findings.…”

Fluorine-Doped LiNi0.8Mn0.1Co0.1O2 Cathode for High-Performance Lithium-Ion Batteries

“…Energies 2020, 13, x 3 of 10 of oxygen with Fions can result in the partial reduction of the transition metal, increasing its ionic radius. Consequently, the c lattice parameter of the NCMF increased, as indicated by a larger dspacing of the (003) plane and a low-angle peak shift ( Figure 1b,c, Supplementary Materials Table S1) [31]. The as-prepared NCM and NCMF samples showed irregular shapes and size distributions, as shown in Figure 2a,b, irrespective of the F doping.…”

“…However, in the NCMF, the replacement of oxygen with F − ions can result in the partial reduction of the transition metal, increasing its ionic radius. Consequently, the c lattice parameter of the NCMF increased, as indicated by a larger d-spacing of the (003) plane and a low-angle peak shift (Figure 1b,c, Supplementary Materials Table S1) [31].…”

The role of metal substitutions in the development of Li batteries, part I: cathodes

“…229,230 In Ni-rich NMC, Ti 4+ substituent increases the reversibility of the H2-H3 phase transition and reduces lower polarization during cycling, which would also improve electrochemical performance. 231 Ti has also been shown to be an effective substitution in NCA. In contrast with NMC, Ti 4+ has been shown to reside in octahedral Li + sites.…”