• Capacity-voltage discharge curve features (CVF): Following Severson et al. , we form a state representation at the start of cycle n by extracting features from the capacity-voltage discharge curve after cycle n -1. We fit each curve to a spline function, linearly interpolating to measure capacity at 1000 evenly spaced voltages from V min to V max . This 1000-dimensional capacity vector Q n-1 is normalised by subtracting the equivalent vector from cycle 0, Q 0 . The following features are then used as inputs: