Fast Li-ion Storage and Dynamics in TiO2 Nanoparticle Clusters Probed by Smart Scanning Electrochemical Cell Microscopy

Anatase TiO2 is a promising material for Li-ion (Li+) batteries with fast charging capability. However, Li+ (de)intercalation dynamics in TiO2 remain elusive and reported diffusivities span many orders of magnitude. Here, we develop a smart protocol for scanning electrochemical cell microscopy (SECCM) with in situ optical microscopy (OM) to enable the high-throughput charge/discharge analysis of single TiO2 nanoparticle clusters. Directly probing active nanoparticles revealed that TiO2 with a size of approximate to 50 nm can store over 30 % of the theoretical capacity at an extremely fast charge/discharge rate of approximate to 100 C. This finding of fast Li+ storage in TiO2 particles strengthens its potential for fast-charging batteries. More generally, smart SECCM-OM should find wide applications for high-throughput electrochemical screening of nanostructured materials.

Automated summary

The study focuses on the material for Li-ion batteries and develops a combination method of scanning electrochemical cell microscopy and in situ optical microscopy for high-throughput charge/discharge analysis of single TiO2 nanoparticle clusters. The research reveals that TiO2 with a size of approximately 50 nm can store over 30% of the theoretical capacity at an extremely fast charge/discharge rate. This finding strengthens the potential of TiO2 for fast-charging batteries and the research method can be widely applied for electrochemical screening of nanostructured materials.