Advanced lithium battery electrodes and characterisation

Simon Engelkeabc (se357@cam.ac.uk)

a Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom

b Institute for Manufacturing, Department of Engineering, 17 Charles Babbage Road, University of Cambridge, Cambridge, CB3 0FS, United Kingdom.

c Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, United Kingdom

There is an ever-increasing demand for batteries with greater capacity and higher rate performance. One approach to improve those characteristics for batteries is to modify their electrode structure to overcome lithium transport limitations. A variety of methods exists to engineer anisotropic structures to enhance diffusion across the electrode including extrusion 1, freeze-drying 2, chemical vapour deposition (CVD) 3, magnetic alignment 4, and templating methods 5. However, direct measurement of 3D diffusion in these non-transparent nanoscale pores is extremely challenging with classic optical techniques. To address this challenge, we developed a technique to measure anisotropic diffusion in a model porous silicon substrate with pulse field gradient (PFG) NMR. We show that NMR provides resolution for solvent (here, H2O, DMSO, and the battery electrolyte LIPF6:DC:EMC) inside and outside of the pores in the Si substrate. When the diffusivity of in-pore NMR peak is analyzed, the root mean squared displacement correlates well with the pore dimensions measured with electron microscopy. These results suggest that PFG NMR can serve as a non-destructive characterisation method for both in- and ex-situ analysis of materials in complex battery electrodes.

Other approaches are to incorporate air into the electrode (lithium-air batteries) and to use liquids as a storage medium (flow batteries). Setting suitable targets and the integration of such batteries into devices and electricity grids will be of great importance.

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5         P. L. Taberna, S. Mitra, P. Poizot, P. Simon and J.-M. Tarascon, High rate capabilities Fe3O4-based Cu nano-architectured electrodes for lithium-ion battery applications, Nat. Mater., 2006, 5, 567–573.

Date & time

11am–2pm 29 Jun 2018

Location

Room:R221

Speakers

Simon Engelke

Contacts

0261250290

Updated:  1 June 2019/Responsible Officer:  Dean, CECS/Page Contact:  CECS Marketing