Investigation of Ionic Conductivity of Electrolytes for Anode-Free Lithium-Ion Batteries by Impedance Spectroscopy

Anode-free lithium-ion batteries offer a volumetric energy density approximately 60% higher than that of conventional lithium-ion cells. Despite this advantage, they often experience rapid capacity degradation and a limited cycle life. Optimizing electrolyte formulations—particularly through the use...

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Main Authors: Azhar Abdrakhmanova, Alfira Sabitova, Binur Mussabayeva, Bulbul Bayakhmetova, Zhanna Sharipkhan, Elmira Yermoldina
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Electrochem
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Online Access:https://www.mdpi.com/2673-3293/6/2/20
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author Azhar Abdrakhmanova
Alfira Sabitova
Binur Mussabayeva
Bulbul Bayakhmetova
Zhanna Sharipkhan
Elmira Yermoldina
author_facet Azhar Abdrakhmanova
Alfira Sabitova
Binur Mussabayeva
Bulbul Bayakhmetova
Zhanna Sharipkhan
Elmira Yermoldina
author_sort Azhar Abdrakhmanova
collection DOAJ
description Anode-free lithium-ion batteries offer a volumetric energy density approximately 60% higher than that of conventional lithium-ion cells. Despite this advantage, they often experience rapid capacity degradation and a limited cycle life. Optimizing electrolyte formulations—particularly through the use of specific additives, solvents, and lithium salts—is essential to improving these systems. This study explores electrolytes composed of fluorinated and carbonate-based solvents applied in anode-free lithium-ion cells featuring copper as the anode substrate and Li<sub>1.05</sub>Ni<sub>0.33</sub>Mn<sub>0.33</sub>Co<sub>0.33</sub>O<sub>2</sub> as the cathode. In the present work, the ionic conductivity of electrolytes was studied by impedance spectroscopy, and the electrochemical parameters of anode-free lithium-ion cells were compared using these electrolyte solutions: lithium difluoro(oxalato)borat (LIDFOB) salts were used in a mixture of solvents such as fluoroethylene carbonate (FEC) and dimethoxyethane (DME) in a ratio of 3:7 and in a mixture of propylene carbonate (PC) and dimethoxyethane in a ratio of 3:7. Enhanced performance was observed upon the substitution of conventional carbonates with fluorinated co-solvents. The findings suggest that LiDFOB is a thermostable salt, and its high conductivity contributes to the formation and stabilization of the interface of solid electrolytes. The results indicate that at low temperature conditions, a double salt should be used for lithium current sources, for example, 0.4 M LiDFOB and 0.6 M LiBF<sub>4</sub>, as well as electrolyte additives such as fluoroethylene carbonate and lithium nitrate.
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spelling doaj-art-1b1aeec550e148b9ac58eef2cbb3c9172025-08-20T03:27:18ZengMDPI AGElectrochem2673-32932025-05-01622010.3390/electrochem6020020Investigation of Ionic Conductivity of Electrolytes for Anode-Free Lithium-Ion Batteries by Impedance SpectroscopyAzhar Abdrakhmanova0Alfira Sabitova1Binur Mussabayeva2Bulbul Bayakhmetova3Zhanna Sharipkhan4Elmira Yermoldina5Department of Chemistry and Ecology, Shakarim University, Semey 071412, KazakhstanDepartment of Chemistry and Ecology, Shakarim University, Semey 071412, KazakhstanPedagogical Institute, Astana International University, Astana 010017, KazakhstanDepartment of Chemistry and Ecology, Shakarim University, Semey 071412, KazakhstanDepartment of Chemistry and Ecology, Shakarim University, Semey 071412, KazakhstanThe Laboratory of Subjects of Natural Mathematics and STEM Technology, National Academy of Education Named After Ybyrai Altynsarin, Astana 010000, KazakhstanAnode-free lithium-ion batteries offer a volumetric energy density approximately 60% higher than that of conventional lithium-ion cells. Despite this advantage, they often experience rapid capacity degradation and a limited cycle life. Optimizing electrolyte formulations—particularly through the use of specific additives, solvents, and lithium salts—is essential to improving these systems. This study explores electrolytes composed of fluorinated and carbonate-based solvents applied in anode-free lithium-ion cells featuring copper as the anode substrate and Li<sub>1.05</sub>Ni<sub>0.33</sub>Mn<sub>0.33</sub>Co<sub>0.33</sub>O<sub>2</sub> as the cathode. In the present work, the ionic conductivity of electrolytes was studied by impedance spectroscopy, and the electrochemical parameters of anode-free lithium-ion cells were compared using these electrolyte solutions: lithium difluoro(oxalato)borat (LIDFOB) salts were used in a mixture of solvents such as fluoroethylene carbonate (FEC) and dimethoxyethane (DME) in a ratio of 3:7 and in a mixture of propylene carbonate (PC) and dimethoxyethane in a ratio of 3:7. Enhanced performance was observed upon the substitution of conventional carbonates with fluorinated co-solvents. The findings suggest that LiDFOB is a thermostable salt, and its high conductivity contributes to the formation and stabilization of the interface of solid electrolytes. The results indicate that at low temperature conditions, a double salt should be used for lithium current sources, for example, 0.4 M LiDFOB and 0.6 M LiBF<sub>4</sub>, as well as electrolyte additives such as fluoroethylene carbonate and lithium nitrate.https://www.mdpi.com/2673-3293/6/2/20ionic conductivity of electrolytesimpedance spectroscopy methoddifluorine(oxalato)lithium boratefluoroethylene carbonatedimethoxyethaneelectrolyte for lithium current sources
spellingShingle Azhar Abdrakhmanova
Alfira Sabitova
Binur Mussabayeva
Bulbul Bayakhmetova
Zhanna Sharipkhan
Elmira Yermoldina
Investigation of Ionic Conductivity of Electrolytes for Anode-Free Lithium-Ion Batteries by Impedance Spectroscopy
Electrochem
ionic conductivity of electrolytes
impedance spectroscopy method
difluorine(oxalato)lithium borate
fluoroethylene carbonate
dimethoxyethane
electrolyte for lithium current sources
title Investigation of Ionic Conductivity of Electrolytes for Anode-Free Lithium-Ion Batteries by Impedance Spectroscopy
title_full Investigation of Ionic Conductivity of Electrolytes for Anode-Free Lithium-Ion Batteries by Impedance Spectroscopy
title_fullStr Investigation of Ionic Conductivity of Electrolytes for Anode-Free Lithium-Ion Batteries by Impedance Spectroscopy
title_full_unstemmed Investigation of Ionic Conductivity of Electrolytes for Anode-Free Lithium-Ion Batteries by Impedance Spectroscopy
title_short Investigation of Ionic Conductivity of Electrolytes for Anode-Free Lithium-Ion Batteries by Impedance Spectroscopy
title_sort investigation of ionic conductivity of electrolytes for anode free lithium ion batteries by impedance spectroscopy
topic ionic conductivity of electrolytes
impedance spectroscopy method
difluorine(oxalato)lithium borate
fluoroethylene carbonate
dimethoxyethane
electrolyte for lithium current sources
url https://www.mdpi.com/2673-3293/6/2/20
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