• • OAR activation occurs at a moderate voltage of 4.1 V in amorphous Li-V-O-F, contrasting with typical high-voltage (>4.5 V) activation in crystalline layered oxides, enabling lower operational stress and improved safety.
• • The fluorinated crystalline LiVO2.98F0.02 (F2) cathode undergoes complete amorphization after the initial cycle, with only a small fraction of rock-salt nanodomains remaining, which fully convert in subsequent cycles, indicating a structural transformation that stabilizes reversible OAR.
• • RIXS and XAS analyses confirm the absence of oxidized oxygen species during initial charging, instead revealing O-O formal redox with electron holes accommodated via O-O interactions, leading to reversible O-O dimerization in the amorphous phase.
• • The OAR mechanism in tetrahedrally coordinated VO4 units, rather than octahedral TM-O configurations, expands the design space for cathode materials, potentially enabling higher energy densities through disordered or amorphous structures.