Abstract

Structural batteries utilise the bifunctionality of carbon fibres to act as a load-bearing structure, but also as a conductive current collector for a battery electrode. Lithium-ion transport during the cycling of structural battery cathodes coated with different morphologies is investigated using Iron X-Ray Absorption Near Edge Spectroscopy (Fe XANES) and correlated to electrochemical performance. Two contrasting morphologies were produced using slurry coating and electrophoretic deposition (EPD) of lithium-iron phosphate (LFP) onto continuous carbon fibres. The ability to study the different structural battery cathode morphologies operando allows for a comparative analysis of their impact on cycling performance. The EPD-coated fibres exhibited a more homogeneous, thinner coating around the fibre compared to the thick, one-sided coating produced using slurry coating. Despite a lower initial capacity and 30 % lithium re-intercalation loss in the first cycle, EPD-coated fibres exhibited more stable capacity retention over time compared to slurry-coated counterparts. Electrochemical Impedance Spectroscopy (EIS) revealed initially high ionic resistance for the EPD-coated fibres, but a larger increase in resistance in the slurry coated electrodes over multiple cycles. This study demonstrated an innovative and novel method of analysing in greater detail, the cycling ability of the coated cathode material on carbon fibres using synchrotron radiation.
Original languageEnglish
Article number236050
JournalJournal of Power Sources
Volume630
Early online date3 Jan 2025
DOIs
Publication statusE-pub ahead of print - 3 Jan 2025

Data Availability Statement

Data will be made available on request.

Acknowledgements

Diamond Light Source is acknowledged for providing the beamtime on I18 beamline under the experiment number SP30127. The authors also gratefully acknowledge Matthew Frost and Teiin Carbon Europe GmbH for supplying carbon fibre material.

Funding

This work was financially supported by Engineering and Physical Sciences Research Council Centre for Doctoral Training in Advanced Automotive Propulsion Systems (AAPS), under the project EP/S023364/1. Financial support was also provided by GKN Aerospace. Additional support was provided by the 2DTECH VINNOVA Competence Centre (Ref. 2019-00068), the USAF EOARD (Award No. FA8655-21-1-7038), and the ONR, USA (Award No. N62909-22-1-2037)

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