Our group is an energy material lab with specific interests in designing, fabricating, characterizing and applying advanced materials for energy conversion and storage, micro-electronics and renewable energy applications. We are interested in tracking critical questions related to advanced materials and fundamental, technological issues. Our goal is to be able to design new materials with revolutionary properties for next-generation energy applications, e.g., energy storage and conversion, as well as to contribute new insights into the chemical/material origins by applying a range of advanced material manufacturing technologies and operando characterization tools developed in our group and the field.

In-situ characterizations are powerful platforms to probe the evolution of active materials during, but not limited to, electrochemical reactions. By employing a liquid in situ transmission electron microscopy (TEM) system, we constitute the first step towards realizing the real-time observation of the nucleation and growth of lithium sulfides from liquid polysulfides on a heterogeneous host. We have also applied the in-situ TEM technique to study the volume expansion, phase evolution, reaction kinetics of advanced electrode materials in rechargeable batteries (e.g., Li-ion, Na-ion and Li-S batteries).

Overview

In-situ characterization

Electrolyte design 

Reversible intercalation of guest ions in graphite is the key feature utilized in modern battery technology. In particular, the capability of Li-ion insertion into graphite enabled the successful launch of commercial Li-ion batteries 30 years ago. On the road to explore graphite as a universal anode for post Li-ion batteries, the conventional intercalation chemistry is being revisited, and our recent findings indicate that alternative intercalation chemistry involving the insertion of solvated ions, could overcome some of the obstacles presented by the conventional intercalation of graphite. We have realized fast-charging graphite anodes in Na-ion batteries and Ca-ion batteries by co-intercalation reactions, which were perceived as impossible before.

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Multivalent ion batteries

Lithium-ion batteries (LIBs) have dominated the energy storage market for more than two decades; however, the quest for lower-cost, higher energy and better safety battery alternatives is rapidly expanding, especially for large-scale applications. Our group is interested in metal-sulfur and multivalent ion batteries. For metal-sulfur batteries, we focus on exploring novel cathode materials such as black phosphorous quantum dots as catalysts and discovering new electrochemical science through in-situ characterizations and theoretical calculations. For multivalent ion batteries, our research interest lies in design nonaqueous electrolytes and new electrode materials.

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