Copper-substituted Na_0.67Ni_0.3−xCu_xMn_0.7O₂ cathode materials for sodium-ion batteries with suppressed P2–O2 phase transition

Abstract

<italic>In situ</italic> XRD resolves the structural evolution of the Na–Cu/Ni/Mn–O system during the Na intercalation/deintercalation processes. The introduction of Cu²⁺ into the transition metal lattice is an strategy to prevent P2–O2 phase transitions.