Nanoscale operation of Ni-Rich cathode surface by polycrystalline solid electrolytes Li3.2Zr0.4Si0.6O3.6 coating

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

“…Moreover, the 3 wt % NCA-Ta 2 O 5 sample represents the best capacity retention (Figure b). The decreased capacity retention of 4 wt % NCA-Ta 2 O 5 may be due to the weakened conductivity of particles caused by a thick coating. − These results reveal that an appropriate amount of Ta 2 O 5 modification is conducive to the cycling stability of NCA during long-term cycling. This is because (1) the Ta 2 O 5 coating layer can reduce the direct contact area between the electrolyte and the cathode material, thereby inhibiting the occurrence of side reactions during the period and further reducing the oxidation of the cathode material during the charging process and improve its cycle stability .…”

Challenges and Strategies towards Single‐Crystalline Ni‐Rich Layered Cathodes

“…Crystal facet regulation has also been shown to effectual. More active surface exposure, such as (012), (104), and (010) facets, etc., could powerfully increase the capacity and rate performance due to the efficient Li diffusion, while more inactive surface exposures, including (001) facet, could enhance the cycling stability at high-voltage due to the suppressed interfacial side reactions and surface phase transitions. Furthermore, well-designed chemical compositions could achieve the expected structural and electrochemical properties.…”

“…[28c,50a,55,56] In general, various crystal facets possess different surface energies, atomic arrangements, and surface reactivities with electrolytes, which could greatly affect the Li diffusion kinetics, transition metal segregations, material crystallinity, and the surface reconstruction of SCNCs. [26a,28c,49,50,51,55-57] Based on DFT calculations, the equilibrium particle shapes of single-crystalline NMC cathodes were mainly composed of nonpolar (104), polar (001), and polar (012) facets, which could be effectively tuned by changing the chemical potentials of oxygen and lithium during synthesis. [50a,55,56] Especially, as shown in Figure 6i, compared with the (012) surface, more (104) surface exposure could be achieved by decreasing the oxygen chemical potential conditions (less O 2 atmosphere, and/or decreased calcinating temperature and time), while higher percentage of exposed (001) facets were obtained by decreasing lithium chemical potential.…”

“…In summary, by exposing more active surfaces, such as ( 012), (104), and (010) facets, etc., the capacity and rate performance could be significantly improved due to the increased Li + diffusion kinetics derived from the efficient Li + diffusion pathways, while the cycling stability at high-voltage could be enhanced by exposing more inactive surfaces, including (001) facet, which could effectively suppress the parasitic side reaction with electrolyte and the adverse surface phase transitions.…”

“…), electrical conductors (e.g., carbon, [86] graphene, [87] polyaniline, [88] polypyrrole, [89] RuO 2 [90] etc. ), and lithium-ion conductors (e.g., Li 3 VO 4 , [91] LiV 2 O 4 , [92] Li 2 MoO 4 , [93] LiNbO 3 , [94] Li 2 SiO 3 , [95] Li 4 SiO 4 , [96] Li 2 TiO 3 , [97] Li 4 Ti 5 O 12 , [98] Li 2 MnO 3 , [99] Li 3 PO 4 , [100] LiAlO 2 , [5d,101] LiAlSiO 4 , [102] Li 2 ZrO 3 , [94b,103] Li 3.2 Zr 0.4 Si 0.6 O 3.6 , [104] Li 3x La 2/3−x TiO 3 , [105] Li 1.4 Y 0.4 Ti 1.6 (PO 4 ) 3 , [106] Li 1.8 Sc 0.8 Ti 1.2 (PO 4 ) 3 [107] etc.). The main modification mechanisms are as follows: 1) promote the interfacial ion/electron transportation by coating ion/ electron conductors; 2) inhibit the interfacial parasitic reactions acted as an electrolyte barrier; 3) alleviate the surface phase transformation and lattice oxygen evolution by providing chemical bonding and physical protective layer; 4) remove the surface residual lithium by reacting with Li compounds.…”