Hybrid Polymer-Liquid Electrolytes and Their Interfaces Towards Electrode Materials for Lithium Ion Batteries
Authors: Cattaruzza Martina , Johansson Mats , Lindbergh Goran , Liu Fang 
Published: December 2024

The escalating demand for efficient, safe, and sustainable energy storage solutions has highlighted lithium-ion batteries (LIBs) as pivotal in the transition towards renewable energy and electrification of society. Despite their widespread adoption, driven by superior energy density, longevity, and low self-discharge rates, LIBs present challenges concerning safety, cost, and environmental impact. The liquid electrolytes traditionally used in LIBs show safety hazards due to their flammability and potential for leakage which impede the utilization of high-voltage cathode materials, thus limiting overall battery performance and reliability.

This study focuses on the exploration and implementation of hybrid polymer-liquid electrolytes (HEs) as a novel approach to circumvent these challenges. HEs, characterized by their unique combination of solid and liquid phases, aim to leverage the benefits of both electrolyte types to enhance safety while maintaining good thermal stability and ionic conductivity. Particularly, the research is focused on the process known as polymerization-induced phase separation (PIPS) consisting in the synthesis of HEs with distinct phase-separated systems, where a liquid ion-conducting phase percolates the macropores and mesopores of the formed thermoset encapsulating phase. The electrochemical performance of such a system depends on the chemical interaction between the liquid and the polymer phase and on the nm-scale morphology of the structure [1]. In this context, the pivotal role of interfaces within LIBs is analyzed, with an emphasis on the electrochemical processes at electrode-electrolyte interfaces that are crucial for the operational efficiency and lifespan of batteries. The study investigates commercial cathode materials highlighting their respective merits and challenges in relation to HEs. The primary objective of this investigation is to evaluate the feasibility of infusing cathode materials and to show that PIPS is possible within both micron-sized and nano-sized confined spaces. By incorporating these HE-infused electrodes into half-cell configurations, the study aims to prove their compatibility with high voltage electrode materials exhibiting energy density and battery performance comparable with traditional systems. A significant focus is placed on assessing the morphological and electrochemical stability of HEs after cycling, validating their practicality and effectiveness in enhancing battery safety while preserving efficiency.

This research endeavors to push the boundaries of current battery technology, proposing innovative solutions to longstanding challenges. By exploring the synergistic effects of HEs with a broader selection of cathode materials, the study aims to contribute valuable insights towards the development of safer, more efficient, and environmentally friendly LIBs.

Acknowledgements

The Swedish Energy Agency (grant #48488) is gratefully acknowledged for financial support.

References

[1] M. Cattaruzza, Y. Fang, I. Furó, G. Lindbergh, F. Liu, and M. Johansson, "Hybrid polymer–liquid lithium ion electrolytes: effect of porosity on the ionic and molecular mobility," Journal of Materials Chemistry A, 10.1039/D3TA00250K vol. 11, no. 13, pp. 7006-7015, 2023, doi: 10.1039/D3TA00250K.