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Fibre Optic Sensor for Characterisation of Lithium‐Ion Batteries
Author(s) -
Hedman Jonas,
Nilebo David,
Larsson Langhammer Elin,
Björefors Fredrik
Publication year - 2020
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.202001709
Subject(s) - cyclic voltammetry , electrode , lithium (medication) , materials science , lithium iron phosphate , electrochemistry , ion , lithium niobate , signal (programming language) , analytical chemistry (journal) , battery (electricity) , optical fiber , optoelectronics , chemistry , optics , computer science , programming language , endocrinology , physics , organic chemistry , chromatography , quantum mechanics , medicine , power (physics)
The interaction between a fibre optic evanescent wave sensor and the positive electrode material, lithium iron phosphate, in a battery cell is presented. The optical–electrochemical combination was investigated in a reflection‐based and a transmission‐based configuration, both leading to comparable results. Both constant current cycling and cyclic voltammetry were employed to link the optical response to the charge and discharge of the battery cells, and the results demonstrated that the optical signal changed consistently with lithium ion insertion and extraction. More precisely, cyclic voltammetry showed that the intensity increased when iron was oxidised during charge and then decreased as iron was reduced during discharge. Cyclic voltammetry also revealed that the optical signal remained unchanged when essentially no oxidation or reduction of the electrode material took place. This shows that optical fibre sensors may be used as a way of monitoring state of charge and electrode properties under dynamic conditions.