Fast Li‐ion Storage and Dynamics in TiO<sub>2</sub> Nanoparticle Clusters Probed by Smart Scanning Electrochemical Cell Microscopy
Emmanuel Batsa Tetteh, Dimitrios Valavanis, Enrico Daviddi, Xiangdong Xu, Carla Santana Santos, Edgar Ventosa, Daniel Martín‐Yerga, Wolfgang Schuhmann, Patrick R. Unwin
Abstract
Abstract Anatase TiO 2 is a promising material for Li‐ion (Li + ) batteries with fast charging capability. However, Li + (de)intercalation dynamics in TiO 2 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 TiO 2 nanoparticle clusters. Directly probing active nanoparticles revealed that TiO 2 with a size of ≈50 nm can store over 30 % of the theoretical capacity at an extremely fast charge/discharge rate of ≈100 C. This finding of fast Li + storage in TiO 2 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.