Fluoride shuttle batteries (FSBs) are expected to have high energy densities. Evolution of FSB reactions, defluorination and fluorination of a nearly two-dimensional cluster of orthorhombic BiF3 microparticles partly embedded in a gold plating film (o-BiF3/gold) was studied by in-situ Raman microscopy. Solutions of fluorobis(2,4,6-trimethylphenyl)borane (FBTMPhB) and CsF (0.45 M and about 0.5 M (saturation)) in tetraglyme were used as electrolytes. During defluorination in the 0.45 M CsF solution, metallic bismuth appeared not only at positions of the cluster but also at positions of the gold plating, accompanying changes in morphology of the cluster, indicating that a dissolution-deposition mechanism (BiF3 -> Bi3+ + 3F(-), Bi3+ + 3e(-) -> Bi) was operative in defluorination. Deposition of metallic bismuth preferentially occurred in the vicinity of the cluster, resulting in extension of protruding areas on the surface. BiF3 with a hexagonal structure appeared during fluorination together with change in the morphology of the cluster. With 0.5 M CsF solution, changes in morphology of the cluster during defluorination and fluorination were small, suggesting that the contribution of the dissolution-deposition mechanism was small. The observed changes in distribution and morphology of active materials will be useful information for designing better electrolytes and electrodes in future batteries. (C) 2019 The Electrochemical Society.