Quantifying the factors limiting rate-performance in battery electrodes

摘要: One weakness of batteries is the rapid falloff in charge-storage capacity with increasing charge/discharge rate. Rate performance related to timescales associated charge/ionic motion both electrode and electrolyte. However, no general fittable model exists link capacity-rate data electrode/electrolyte properties. Here we demonstrate an equation which can fit versus rate data, outputting three parameters fully describe rate performance. Most important characteristic time be linked by a second physical via various rate-limiting processes. We these equations ~200 sets, deriving such as diffusion coefficients or electrolyte conductivities. It possible show processes are dominant given situation, facilitating rational design cell optimisation. In addition, this predicts upper speed limit for lithium/sodium ion batteries, yielding value that consistent fastest electrodes literature. The authors employ semi-empirical method published battery extract charge/discharge. These times used rate performance properties electrodes.