Liquid Phase Electron Microscopy at High-Spatial Resolution or Elevated Temperatures

Recent developments in liquid-phase transmission electron microscopy holder technologies have enabled higher spatial resolution, better analytical capabilities, and control of temperature and applied bias for electrochemical measurements.[1] These developments include thinner window layers, new designs of heating and electrochemical signal circuits, as well as better control of the liquids flowing through the sample region. Over the last several years, we have worked on both graphene liquid cell [2] and conventional MEMS-based liquid-phase electron microscopy sample holders, demonstrating that atomic-resolution imaging and electron energy-loss spectroscopy (EELS) can be achieved at sufficiently low dose rates.

In this presentation, I will highlight our latest graphene liquid cell approaches and how the improved tolerance of samples encapsulated by the ultrathin graphene window layers can be used to perform atomic-resolution analysis of ceria nano-particles. Specific examples will include i) colloidal ceria hosts with Er spin defects for use as qubits with nearly milliseconds spin coherence [3]; and ii) ceria nanoparticles decorated with chondroitin sulfate A (CSA) for use as an antibacterial oral rinse. [4]

When studying multivalent battery chemistries and their evolution during repeated charge/discharge cycles, elevated temperature conditions are needed, especially when ionic-liquid electrolytes are used. Over the last few years, we have developed an integrated heating and electrochemistry holder, allowing us to quantify structural changes in individual battery cathode particles during cycling at temperatures up to 150° C. Here, I will show how this setup can be used to study the amorphization of MgV₂O₄ during Mg extraction at 120° C.[5]

References:
[1] Ercius, P., J.A. Hachtel, and R.F. Klie, Chemical and bonding analysis of liquids using liquid cell electron microscopy. MRS Bulletin, 2020. 45(9): p. 761-768.
[2] Wang, C., Q. Qiao, T. Shokuhfar, and R.F. Klie, High-Resolution Electron Microscopy and Spectroscopy of Ferritin in Biocompatible Graphene Liquid Cells and Graphene Sandwiches. Advanced Materials, 2014. 26: p. 3410–3414.
[3] Wong, J., M. Onizhuk, J. Nagura, A.S. Thind, J.K. Bindra, C. Wicker, G.D. Grant, Y. Zhang, J. Niklas, O.G. Poluektov, R.F. Klie, J. Zhang, G. Galli, F.J. Heremans, D.D. Awschalom, and A.P. Alivisatos, Coherent Erbium Spin Defects in Colloidal Nanocrystal Hosts. ACS Nano, 2024. 18(29): p. 19110-19123.
[4] Ellepola, K., L. Bhatt, L. Chen, C. Han, F. Jahanbazi, R.F. Klie, F.L. Vargas, Y.B. Mao, K. Novakovsky, B. Sapkota, and R.P. Pesavento, Nanoceria Aggregate Formulation Promotes Buffer Stability, Cell Clustering, and Reduction of Adherent Biofilm in Streptococcus mutans. ACS Biomaterials Science & Engineering, 2023. 9(8): p. 4686-4697.
[5] The work presented here was supported by the National Science Foundation (CBET-2312359), the NSF Center for Chemical Innovation MOSAIC (CHE-2420536) and by the Army Research Office under Grant Number W911NF-23-1-0225. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Office or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes, notwithstanding any copyright notation herein.