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NUANCE Researchers Reveal More on Conversion Reaction Mechanism for High-Capacity Lithium-ion Battery


Atomic Resolution Study of Reversible Conversion Reaction
in Metal Oxide Electrodes for Lithium-Ion Battery by In-situ TEM,
  Langli Luo, Jinsong Wu, Junming Xu, and Vinayak P. Dravid,
ACS Nano (22 October 2014).

http://pubs.acs.org/doi/abs/10.1021/nn504806h


ACS Nano

There is an urgent need to develop high capacity batteries to power electric vehicles and to store energy generated from renewable sources. Researchers at the NUANCE Center – EPIC Facility at Northwestern University have investigated reversible conversion reaction between oxide and lithium at atomic resolution by in-situ transmission electron microscopy (TEM).1 Electrode materials based on conversion reactions with lithium ions have shown much higher energy density than those based on intercalation reactions, while its reaction mechanism remains unclear. Being able to look into the revisable conversion and deconversion reaction between Co3O4/Graphene and lithium in the charge/discharge cycles, detailed mechanism on the reaction which could be the basis to build high-capacity lithium-ion battery has been revealed. During lithiation, the lithium inserted Co3O4 phase and a phase consisting of nano-sized Co-Li-O clusters are identified as the intermediate products prior to the subsequent formation of Li2O crystals. In delithiation, the reduced metal nanoparticles form a network and breakdown into even smaller clusters that act as catalysts to prompt reduction of Li2O, and CoO nanoparticles, which are identified as the product of deconversion reaction. Such direct real-space, real-time atomic-scale observations shed light on the phenomena and mechanisms in reaction-based electrochemical energy conversion and provide impetus for further development in electrochemical charge storage devices. Such in-situ observations of reaction pathway and conversion stages may provide necessary insights into further development of high power lithium-air batteries based on reversible oxidation and reduction of Li2O.

The experiments were performed at the Northwestern University Atomic and Nanoscale Characterization Experimental (NUANCE) center, while the in-situ TEM holder and the glove box were acquired through the support of Northwestern Core-Facility Fund. The work was completed by Langli Luo (Postdoctoral Researcher at the NUANCE center), Jinsong Wu (TEM Manager at the NUANCE Center and Research Assistant Professor with the Department of Materials Science and Engineering at Northwestern University), Junming Xu (Visiting Professor from Hangzhou Dianzi University, Hangzhou, China) and Vinayak Dravid (Director of the NUANCE Center and Abraham Harris Professor with the Department of Materials Science and Engineering at Northwestern University).

  1. L. Luo, J.S. Wu, J. Xu, V.P. Dravid, “Atomic Resolution Study of Reversible Conversion Reaction in Metal Oxide Electrodes for Lithium-Ion Battery”, ACS Nano, 2014, DOI: 10.1021/nn504806h.