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Ion exchange in atomically thin clays and micas

DOI: 10.1038/s41563-021-01072-6 DOI Help

Authors: Yi-Chao Zou (Sun Yat-sen University; The University of Manchester) , Lucas Mogg (The University of Manchester; University of Cambridge) , Nick Clark (The University of Manchester) , Cihan Bacaksiz (Universiteit Antwerpen; Bremen Center for Computational Material Science (BCCMS); Shenzhen JL Computational Science and Applied Research Institute) , Slavisa Milanovic (Universiteit Antwerpen) , Vishnu Sreepal (The University of Manchester) , Guang-Ping Hao (The University of Manchester) , Yi-Chi Wang (The University of Manchester; Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences) , David G. Hopkinson (The University of Manchester) , Roman Gorbachev (The University of Manchester) , Samuel Shaw (The University of Manchester) , Kostya S. Novoselov (The University of Manchester) , Rahul Raveendran-Nair (The University of Manchester) , Francois M. Peeters (Universiteit Antwerpen) , Marcelo Lozada-Hidalgo (The University of Manchester) , Sarah Haigh (The University of Manchester)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Nature Materials , VOL 14

State: Published (Approved)
Published: August 2021
Diamond Proposal Number(s): 21981 , 21597

Abstract: The physical properties of clays and micas can be controlled by exchanging ions in the crystal lattice. Atomically thin materials can have superior properties in a range of membrane applications, yet the ion-exchange process itself remains largely unexplored in few-layer crystals. Here we use atomic-resolution scanning transmission electron microscopy to study the dynamics of ion exchange and reveal individual ion binding sites in atomically thin and artificially restacked clays and micas. We find that the ion diffusion coefficient for the interlayer space of atomically thin samples is up to 104 times larger than in bulk crystals and approaches its value in free water. Samples where no bulk exchange is expected display fast exchange at restacked interfaces, where the exchanged ions arrange in islands with dimensions controlled by the moiré superlattice dimensions. We attribute the fast ion diffusion to enhanced interlayer expandability resulting from weaker interlayer binding forces in both atomically thin and restacked materials. This work provides atomic scale insights into ion diffusion in highly confined spaces and suggests strategies to design exfoliated clay membranes with enhanced performance.

Journal Keywords: Materials science; Nanoscience and technology; Transmission electron microscopy; Two-dimensional materials

Subject Areas: Materials, Earth Science

Diamond Offline Facilities: Electron Physical Sciences Imaging Centre (ePSIC)
Instruments: E02-JEM ARM 300CF

Added On: 02/09/2021 10:02

Discipline Tags:

Earth Sciences & Environment Mineralogy Materials Science Geology

Technical Tags:

Microscopy Electron Microscopy (EM) Scanning Transmission Electron Microscopy (STEM)