Phase evolution in single-crystalline LiFePO₄ followed by in-situ scanning X-ray microscopy of a micrometer-sized battery

We built a micrometer-sized all-solid-state thin film battery to follow in-situ the (de)lithiation mechanism of single crystalline LiFePO₄ along the fast (010) orientation using scanning transmission X-ray microscopy. The starting point of phase transformation is dictated by the respective conductivities reflecting the defect chemical situation, while the growth pattern of both LFP and FP was clearly found to be dominated by elastic effects rather than being transport controlled.