Understanding aggregation hindered Li-ion transport in transition metal oxide at mesoscale

Conversion based transition-metal oxides as a promising class of anode materials, require proper nanostructuring for enhanced Li-ion storage capabilities. However, aggregation is found to be a common issue in nanomaterial systems, and can have detrimental effects on transport properties in composite electrodes. By employing a model transition-metal oxide anode with unique two-dimensional holey nanostructures, we investigated underlying reasons for the limited electrochemical kinetics induced by mesoscale aggregation. Through combined electrochemical and in situ characterization techniques, we demonstrate that aggregation leads to hindered interfacial charge transfer and retarded phase transformation, with the influence on kinetics escalating with more aggregation. These results shed light on more dedicated structural design for effective battery electrodes across multiple length scales.