Dr. Meng Gu
Environmental Molecular Sciences Laboratory
Pacific Northwest National Laboratory, Richland, Washington 99352, USA
Maximizing the usage of renewable energy will reduce our reliance on dwindling natural resources and environmental pollution. Batteries are an important enabling technology for renewable energy, portable electronics, and modern transportation systems such as hybrid electric vehicles. Especially all-solid-state batteries hold the promise of providing high energy density and easy integration into the renewable energy systems such solar and biofuels systems. However, limitation of current materials has to be overcome if long-life and low-cost batteries are to be built. In my talk, I will focus on the study of the traditional Li-ion batteries and all-solid-state batteries using a combination of advanced synthesis and characterization methods. The advances in the aberration-corrected scanning / transmission electron microscopy have enabled the study of physical structure, chemical composition, bonding of complicated chemical substance at the atomic scale and in three dimensions. Li1.2Ni0.2Mn0.6O2 are promising high-capacity cathode materials for replacing the traditional LiCoO2 cathode. Three-dimensional chemical analysis is used to accurately locate and quantitatively analyze the Ni-segregated regions in one single nanoparticle. Important questions such as the failure mechanism, phase transformation process are answered based on the structural information obtained. To address these issues, reducing the chemical segregation and application of surface coatings are shown to significantly improve the electrochemical performance of the batteries. Furthermore, state of the art in-situ microscopy method opens the door for the study of the dynamic changes of the electrodes/electrolyte during electrochemical cycling. The information obtained during the in-situ characterization experiments can be used to direct the development of new electrodes and enhance the capacity and life of batteries. Last but not least, I want to talk about my current research and future plan on the development of all-solid-state batteries and their potential applications as efficient electrochromic materials and energy storage devices. Pulsed laser deposition technique can be used to synthesis and fabricate all-solid-state batteries with many advantages. The application of atomic-resolution in-situ TEM analysis of the all-solid-state batteries are of great importance to reveal their unknown functional mechanism.