Towards Li-Ion Batteries Operating at 80 °C: Ionic Liquid versus Conventional Liquid Electrolytes

Gabriel Oltean,Torbjörn Gustafsson,Wei Wei,Chao Xu,Leif Nyholm,Nareerat Plylahan,Patrik Johansson,Kristina Edström,Charlotte Ihrfors

doi:10.3390/batteries4010002

Gabriel Oltean, Torbjörn Gustafsson + Show 7 more

Open Access

https://doi.org/10.3390/batteries4010002

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Journal: Batteries	Publication Date: Jan 2, 2018
Citations: 12	License type: CC BY 4.0

Affiliation: Uppsala University, Chalmers University of Technology

Abstract

Li-ion battery (LIB) full cells comprised of TiO2-nanotube (TiO2-nt) and LiFePO4 (LFP) electrodes and either a conventional organic solvent based liquid electrolyte or an ionic liquid based electrolyte have been cycled at 80 °C. While the cell containing the ionic liquid based electrolyte exhibited good capacity retention and rate capability during 100 cycles, rapid capacity fading was found for the corresponding cell with the organic electrolyte. Results obtained for TiO2-nt and LFP half-cells indicate an oxidative degradation of the organic electrolyte at 80 °C. In all, ionic liquid based electrolytes can be used to significantly improve the performance of LIBs operating at 80 °C.

Highlights

Due to their high energy and power densities, state-of-the-art Li-ion batteries (LIBs) are widely used for portable electronics, as well as for electric and hybrid electric vehicles
These results indicate that the TiO2 -nt electrodes readily can be used at 80 ◦ C
The electrochemical cycling performance of cells composed of TiO22-nt negative electrodes and LFP positive electrodes at 80 ◦ C critically depends on the choice of the electrolyte

Summary

Introduction

Due to their high energy and power densities, state-of-the-art Li-ion batteries (LIBs) are widely used for portable electronics, as well as for electric and hybrid electric vehicles. With LIBs working at elevated temperatures—e.g., between 80 and 100 ◦ C—the thermal management in a hybrid electric vehicle could be significantly simplified by allowing the cooling system for the power electronics to take care of the cooling of the battery pack, resulting in a significant reduction in the complexity and price [5]. The extensive work with traditional carbonate electrolytes has aimed at finding suitable electrolyte additives [7], alternative binders [8], and the failure mechanisms for both the negative [9,10]

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