Hiring Institution
Institut de Chimie et des Matériaux Paris-Est (ICMPE)

PhD-Awarding Institutions
Université Paris-Est Créteil (UPEC)
University of New South Wales (UNSW)

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Option 1

Polymer-ionic liquid composites for lithium-ion batteries: toward new polymer based solid electrolytes

The proposed project concerns the synthesis of new solid electrolyte membranes based on thermostable polymers and ionic liquids (ILs) for being used as ion-conducting membranes in lithium-ion batteries (LIBs). The originality of this approach lies in the use of polycyanurates (PCNs), a family of thermosetting polymers with unique intrinsic properties (high chemical and thermal resistance, low dielectric constant and strong adhesion to conductive metals and composites) as polymer matrix for impregnating ILs. These polymers have mainly been used as binders in high performance structural composites, especially in the aeronautical and aerospace industry but have not been exploited in the microelectronics industry yet because of their brittleness while suitable polymer materials used in microelectronic devices must be flexible. Recently, we have found that the presence of a small amount of ILs during the step of forming PCN networks produces flexible conductive PCN-ILs membranes that could replace both microporous separators and flammable volatile organic electrolytes in Li-ion batteries. Indeed, thanks to the presence of nano-domains containing ILs, these membranes would facilitate the mobility of Li+ cations while maintaining the electronic insulation even at a high temperature. They would also act as a physical barrier against dendritic growth, hence reducing the risk of short circuit, thermal runaway, explosion and thus significantly improving the safety of LIBs and therefore would enable to replace conventional anodic materials, i.e. graphite, by metallic lithium one for producing metallic lithium batteries (MLBs) with very high energy density. It is noteworthy to mention that the impregnation of ILs would endow the membranes with the ionic conductivity with improved safety issues thanks to the non-volatility, non-flammability and no leakage of impregnated ILs. Moreover, recent studies show that the use of ILs can significantly increase the electrochemical properties of a solid-state battery, such as improving the long-term stability of lithium metal electrodes and the interfacial compatibility with electrodes. The main objective of this PhD project will be the development of high-performance ion-conducting membranes based on PCNs/ILs composites for being used in LIBs and MLBs.

Option 2

Thermostable polymer/IL composites for applications in next generation Na-ion batteries

Among the various types of electrochemical energy storage technologies, Li+-ion batteries are still in the forefront and are currently playing an indispensable role in supporting our modern society. Electrochemistry of lithium-based cell presents various attractive properties: i) lithium is the lightest metal with an exceptional low redox potential (ELi+/Li = −3.04 V/NHE); ii) Li+-ion possesses a small ionic radius that is advantageous for easy diffusion into solid; iii) Li+-ion based cell has a long cycle life with high rate capability etc. Unfortunately, lithium resources are limited: only 20 ppm as relative abundance in the Earth’s crust. Thus, many researchers try to explore new abundant and low-cost alternatives to lithium such as sodium, potassium or calcium. Sodium is cheap, available in a high abundance (1000 times more abundant than lithium) with very desirable redox potential, i.e. ENa+/Na = −2.71 V/NHE, only 0.3 V greater than that of lithium, and similar electrochemical behaviour. The proposed project concerns the synthesis of new solid electrolyte membranes based on thermostable polymers and ionic liquids (ILs) for being used as ion-conducting membranes in sodium-ion batteries (SIBs). The originality of this approach lies in the use of polycyanurates (PCNs), a family of thermosetting polymers with unique intrinsic properties (high chemical and thermal resistance, low dielectric constant and strong adhesion to conductive metals and composites) as polymer matrix for impregnating ILs. These polymers have been mainly used as binders in high performance structural composites, especially in the aeronautical and aerospace industry but have not yet been exploited in the microelectronics industry because of their brittleness. Recently, we have found that the presence of a small amount of ILs during the step of forming PCN networks produces flexible conductive PCN-ILs membranes that could replace both microporous separators and flammable volatile organic electrolytes in Li-ion batteries. Indeed, the presence of nano-domains containing ILs within these membranes would facilitate the mobility of Na+ cations while maintaining the electronic insulation even at a high temperature. They should act as a physical barrier against dendritic growth, hence reducing the risk of short circuit, thermal runaway, explosion and thus, significantly improving the safety of Na-ion batteries and therefore would enable to replace conventional graphite based anode by metallic sodium for producing batteries with very high energy density. The impregnation of ILs would endow the membranes with ionic conductivity with improved safety issues thanks to the non-volatility, non-flammability and no leakage of impregnated ILs. Recent studies show that the use of ILs can significantly increase the electrochemical properties of a solid-state battery, such as improving the long-term stability of metal electrodes and the interfacial compatibility with electrodes.

Option 3

Ionic liquids-biosourced polymer based composites meant for sustainable Li-ion batteries

The proposed project concerns the synthesis of high-performance solid electrolyte membranes based on biosourced thermostable polymers and ionic liquids (ILs) for being used as ion-conducting membranes in lithium-ion batteries (LIBs). The originality of this approach lies in the use of biosourced polycyanurates (PCNs), a family of thermosetting polymers with unique intrinsic properties (high chemical and thermal resistance, low dielectric constant and strong adhesion to conductive metals and composites) as polymer matrix for impregnating ILs. These polymers have mainly been used as binders in high performance structural composites, especially in the aeronautical and aerospace industry but have not been exploited in the microelectronics industry yet because of their brittleness. Recently, we have found that the presence of a small amount of ILs during the step of forming PCN networks produces flexible conductive PCN-ILs membranes that could replace both microporous separators and flammable volatile organic electrolytes in Li-ion batteries. Indeed, thanks to the presence of nano-domains containing ILs, these membranes would facilitate the mobility of Li+ cations while maintaining the electronic insulation even at a high temperature. They would also act as a physical barrier against dendritic growth reducing the risk of short circuit, thermal runaway, explosion and thus significantly improving the safety of LIBs and therefore would enable to replace conventional graphite based anode by metallic sodium for producing batteries with very high energy density. It is worth mentioning that biosourced PCNs will be designed and synthesized from renewable starting materials, thus avoiding the use of toxic bisphenol E. The impregnation of ILs endows the membranes with the ionic conductivity with improved safety issues owing to the non-volatility, non-flammability and no leakage of impregnated ILs. Moreover, recent studies have shown that the use of ILs can significantly increase the electrochemical properties of a solid-state battery, such as improving the long-term stability of lithium metal electrodes or the interfacial compatibility with electrodes.

Rita Baddour-Hadjean
Dipan Kundu

Energy storage, Li (Na) batteries, Chemistry, Polymer science, Materials science, Solid-state chemistry, Electrochemistry