Overall, this study highlights the excellent structural reversibility, phase stability and efficient fluoride ion transport in LaSrMnO4, reinforcing its potential as a suitable cathode material for FIBs by deepening the understanding of the reasons behind it. The critical role of the carbon additive morphology to achieve fluorination to LaSrMnO4F~2 within the charging step is also highlighted, suggesting that additive optimization is crucial to take full advantage of intercalation-based cathodes in fluoride-ion batteries. Thus, for high voltage cathodes in FIBs, the development of alternative conductive mixtures in combination with compositional (and corresponding structural changes, e.g., as would take place for n=2 RP-type compounds) might help to obtain improved properties similar to current LIBs 50