Improving Reversible Capacities of High-Surface Lithium Insertion Materials – The Case of Amorphous TiO2

Chemisorbed water and solvent molecules and their reactivity with components from the electrolyte in high-surface nanostructured electrodes remains a contributing factor towards capacity diminishment on cycling in lithium ion batteries due to the limit in maximum annealing temperature. Here we report a marked improvement in the capacity retention of amorphous TiO2 by the choice of preparation solvent, control of annealing temperature and the presence of surface functional groups. Careful heating of the amorphous TiO2 sample prepared in acetone under vacuum lead to complete removal of all molecular solvent and an improved capacity retention of 220 mAh/g over 50 cycles at a C/10 rate. Amorphous TiO2 when prepared in ethanol and heated under vacuum showed an even better capacity retention of 240 mAh/g. From FTIR Spectroscopy and Electron Energy Loss Spectroscopy measurements, the improved capacity is attributed to the complete removal of ethanol and the presence of very small fractions of residual functional groups coordinated to oxygen-deficient surface titanium sites. These displace the more reactive chemisorbed hydroxyl groups, limiting reaction with components from the electrolyte and possibly enhancing the integrity of the solid electrolyte interface (SEI). The present research provides a facile strategy to improve the capacity retention of nanostructured electrode materials

Following battery electrochemistry using in-situ TEM

In-situ transmission electron microscopy (TEM) offers a powerful tool to directly observe electrochemical processes at the nanoscale, providing critical insights into the mechanisms underlying battery performance and degradation. This talk will delve into the application of in-situ TEM to investigate both all-solid-state and aqueous battery systems.I will discuss specific examples from our research highlighting on how in-situ TEM can enable building better batteries. Additionally, we will explore the unique challenges associated with in-situ TEM studies of batteries, including sample preparation, environmental control, and electron beam damage. By addressing these challenges, we aim to further advance the understanding of battery mechanisms and guide the development of next-generation energy storage devices

Optimization of Solid Oxide Fuel Cell materials: Visualization of Processes via In-Situ Electron Microscopy

In situ observation of SOFC/SOEC materials using in TEM at operation conditions to optimize materials and design paramters of SOC

Visualization of active solid-gas interface using in situ TEM

Power-to-X enables the production of valuable compounds from the CO2 via catalytic reaction for net-zero carbon economy. The understanding of the behaviors of the supported catalyst under the reaction conditions and the elucidating the associated mechanism are crucial for the rational design of high-performing catalyst materials. The understanding and atomic level information provided by aberration-corrected TEM is unparalleled, particularly for the study of catalyst nanoparticles. Post-mortem analysis can make it difficult to underpin the specifics of a catalytic reaction mechanism, without being able to observe the structures under a realistic environment. The development of specialized microelectromechanical systems (MEMS) based sample holder now allows us to contain gas near the sample at more than 1 bar pressure with precise control over heat, gas flow and gas composition