Synergetic stability enhancement with magnesium and calcium ion substitution for Ni/Mn-based P2-type sodium-ion battery cathodes.

ABSTRACT: The conventional P2-type cathode material Na_0.67Ni_0.33Mn_0.67O₂ suffers from an irreversible P2-O2 phase transition and serious capacity fading during cycling. Here, we successfully carry out magnesium and calcium ion doping into the transition-metal layers (TM layers) and the alkali-metal layers (AM layers), respectively, of Na_0.67Ni_0.33Mn_0.67O₂. Both Mg and Ca doping can reduce O-type stacking in the high-voltage region, leading to enhanced cycling endurance, however, this is associated with a decrease in capacity. The results of density functional theory (DFT) studies reveal that the introduction of Mg²⁺ and Ca²⁺ make high-voltage reactions (oxygen redox and Ni⁴⁺/Ni

SUBMITTER: Fu H 

PROVIDER: S-EPMC8768886 | biostudies-literature | 2022 Jan

REPOSITORIES: biostudies-literature