Abstract Vanadium pentoxide (V2O5) is a promising cathode material for sodium-ion batteries due to its high capacity and layered structure that accommodates Na+ intercalation. Despite this potential, how electrode processing, particularly calendering, affects its electrochemical performance remains insufficiently understood. Here, we systematically investigate PVDF-based V2O5 cathodes with and without calendering using complementary electrochemical and structural characterization. Calendering enhanced electrode compactness, reduced microcracking, and lowered ohmic resistance, thereby yielding higher initial specific capacity. It slightly improves performance from the second cycle onward but does not substantially mitigate the first-cycle capacity loss. Although calendering reduces charge-transfer resistance during cycling, calendering beyond a certain limit restricts Na+ transport, reflecting a trade-off between densification and ion diffusion. Overall, our results show that calendering is not universally beneficial: while it enhances mechanical integrity and initial electrochemical performance, excessive densification raises interfacial resistance and compromises ionic transport. Optimizing calendering conditions is therefore critical for next-generation sodium-ion batteries.
Chowdhury et al. (Fri,) studied this question.