Modification of LiNi0.5Co0.2Mn0.3O2 with a NaAlO2 coating produces a cathode with increased long-term cycling performance at a high voltage cutoff

Understanding the Role of Alumina (Al2O3), Pentalithium Aluminate (Li5AlO4), and Pentasodium Aluminate (Na5AlO4) Coatings on the Li and Mn‐Rich NCM Cathode Material 0.33Li2MnO3·0.67Li(Ni0.4Co0.2Mn0.4)O2 for Enhanced Electrochemical Performance

“…[ 54 ] The observed peaks in the Al 2p spectrum at ≈74.0 and ≈72.4 eV correspond to Al 2p 3/2 and Al of the respective coatings (Li‐aluminate and Na‐aluminate). [ 36,37 ] Analysis of Al 2p spectrum for Li‐aluminate and Na‐aluminate samples suggests the presence of two Al‐components: Al 2 O 3 and Al x M y . The latter in situ formed Al x M y phase could be tentatively assigned to Al 25 Ni 75 .…”

“…[ 26,27 ] One of the promising approaches is surface coatings using metal oxides like TiO 2 , [ 28 ] ZrO 2 , [ 29 ] Al 2 O 3 , [ 28,30,31 ] and Li‐ion conducting materials, for instance, lithium aluminate, [ 32–35 ] lithium zirconate, [ 29 ] sodium aluminate. [ 36,37 ] These coatings effectively lessen the undesired detrimental surface reactions of solutions species and HE‐NCM cathodes, diminishing thus TMs dissolution upon prolonged cycling. For instance, Shen et al.…”

“…[ 36 ] In the case of Ni‐rich cathode materials (NCM532), NaAlO 2 ‐coatings also form effective electrode–electrolyte solution interphase that promotes sustainable Li‐ion transport restraining the side reactions during cycling. [ 37 ]…”

“…[ 28,30,31 ] In contrast, the lithium aluminate coatings on these materials bring out the synergistic effect of surface protection due to high chemical stability and faster Li‐ion transport kinetics by reducing the cell impedance upon cycling. [ 32–35 ] The positive impact of sodium aluminate coating on layered cathode materials like LiCoO 2 [ 36 ] or Ni‐rich material (NCM523) [ 37 ] has also been studied where the formation of 2D ion diffusion channels [ 40 ] upon charging has been accounted for the superior electrochemical performances. It is important to emphasize that reducing HF concentrations in the electrolyte solution upon the consecutive electrochemical cycling were also observed for cells comprising alumina coated cathodes [ 41,42 ] as the alumina‐based coatings undergo chemical reactions with harmful HF forming a variety of AlO x F y H z species (including AlF 3 , AlO x H y ), what means effective scavenging of HF.…”

Powder Coatings via Atomic Layer Deposition for Batteries: A Review

“…Oxide, nitride, fluoride, and phosphate surface coatings are among the promising approaches to effectively reduce undesired surface reactions of cathode materials with the solution species to diminish transition metal dissolution amd as a result improve stability and electrochemical performance. Along with these long reported coating materials, some other materials with good lithium-ion conducting property like LiAl 5 O 8 , LiAlO 2 , NaAlO 2 , Li 2 ZrO 3 , Li 3 VO 4 , Li 3 PO 4 , etc. have also been reported in recent years displaying a similar role.…”