Synergic coating and doping effects of Ti-modified integrated layered–spinel Li_1.2Mn_0.75Ni_0.25O_2+δ as a high capacity and long lifetime cathode material for Li-ion batteries

Abstract

The Ti-modified Li1.2Mn0.75Ni0.25O2+δ with core–shell structure has showed better cycling stability than the pristine one.

Ultra‐Thin Coating and Three‐Dimensional Electrode Structures to Boosted Thick Electrode Lithium‐Ion Battery Performance

“…A peak of a Mn 3 + /4 + redox couple of around 4.0 V is also commonly seen in a disordered LMNO structure. [20,21] In addition, there was no significant difference in the CV responses between the samples of a conventional structure and a 3D structure, which was reasonable, since that structure did not affect the chemical properties. The results from CV measurement were consistent with the voltage profiles, as shown in Figure 2g.…”

“…As shown in Figure f, the coated samples (green line range) showed a 40 % smaller difference between the anodic and cathodic peaks than those of the uncoated samples (yellow line range), which suggested a smaller polarization and better conductivity of the coated samples. It was also observed that the coated samples had more significant N i2+/4+ peaks at 4.5 to 4.8 V and Mn 3+/4+ at 3.6 to 4.3 V than the uncoated samples did, which indicated increased amounts of Ni 2+/4+ and Mn 3+/4+ redox couples . The peak of the Ni 2+/4+ redox couple is known as one peak for an ordered LMNO structure, while the Ni exhibits two‐step reactions, including Ni 3+/4+ and Ni 2+/3+ for a disordered LMNO structure.…”

“…As the first step (Figure a), the individual particles were coated with FeO x by ALD, followed by an annealing process. The annealing processing after coating could be considered as doping the particles with FeO x , which might stabilize the active material in the electrolyte, and disorder the structure to improve battery performance . Next, the pastes with particles (coated or non‐coated) were extruded into a 3D hybrid structure (Figure S1) and tape casted as a conventional structure, respectively, and then assembled as a half‐cell (Li foil anode) based on a coin cell design.…”

“…The annealing processing after coating could be considered as doping the particles with FeO x , [18] which might stabilize the active material in the electrolyte, and disorder the structure to improve battery performance. [18][19][20] Next, the pastes with particles (coated or non-coated) were extruded into a 3D hybrid structure ( Figure S1) and tape casted as a conventional structure, respectively, and then assembled as a half-cell (Li foil anode) based on a coin cell design. To confirm the ALD coating layers on the LMNO particle surfaces, Transmission Electron Microscopy (TEM) was used for FeO x coated LMNO particles followed by annealing.…”

Spinel‐layered Li2MnTiO4+z cathode material for Li‐ion batteries prepared by a sol‐gel method

“…Among various doping elements such as Ru, [6] Cr, [7] V, [8] etc., Ti has a lot of advantages including abundant, non-toxic, high bonding with oxygen which can stabilize framework. [9,10] For example, Zhao et al substituted Ti for Mn in 0.5Li2MnO3-0.5LiNi1/2Mn1/2O2, resulting in improving the performance of the cathode material by suppressing transition metal ions dissolution during cycling. [11] Thackeray et al also reported that Ti substituted Mn and Ni in Li(Mn0.46Ni0.46Ti0.05Li0.02)O2 improve capacity as well as cycling stability compared with undoped sample.…”