Insertion reactions are of key importance for Li-ion and Hydrogen storage materials and energy storage devices. Nano-sizing the electrode materials has emerged as a promising strategy to enhance the power density by simply reducing the Li-ion diffusion path length through the electrode material. Recent research on the promising anode material LixTiO2 anatase reveals that nano-sizing has considerably more impact on material properties. If the particle size is decreased below ~70nm anomalous phase transition behaviour has been observed. We are looking for a better understanding of this nano-scale phase behaviour. Therefore we wish to extend our current research with other nanocrystalline materials, at various operating temperatures. The goal is to develop a general theory for nanoscale phase transition behaviour for ion-insertion compounds.