Znak Politechniki Warszawskiej

MOGLiS Project – scientific support for low-emissions economy

Graphics of batteries

The Warsaw University of Technology is the leader of the project consortium, photo: pixabay

Increasing popularity of electric vehicles and growing importance of renewable energy sources have created the necessity to develop new, light, higher-capacity and more efficient energy storage systems, among which the most prominent is electrochemical energy storage (EES).

At present, the EES market is dominated by lithium-ion batteries (LiBs), which may be used in a wide range of applications, starting from small, portable electronic devices, to electric vehicles. However, despite such a wide range of possible applications, development of the currently widely used lithium-ion batteries is somewhat limited, mainly due to the theoretical capacity of the graphite electrode with a cathode based on transition metal oxides (560 Wh kg-1). Therefore, it is necessary to develop technologies which will facilitate production of cells of higher energy density.

How to use the advantages of lithium-sulphur batteries?

One solution is to replace the graphite electrode with metallic lithium and an oxide cathode with a sulphur one, of higher capacity (lithium-sulphur batteries – Li-S). Li-S batteries are especially attractive due to their much higher theoretical capacity (1675 mAh g-1) and energy density (2500 Wh kg-1) at average working voltage of 2.5 V. So high energy density makes this type of battery a very promising research goal for applications in light energy storage systems.

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At present, the main challenges related to Li-S batteries include low electron conductivity of elemental sulphur, big changes in the volume of the cathode during charging/discharging and loss of elemental sulphur – the cathode’s active material, due to high solubility of lithium polysulphides in the organic electrolyte.

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The main problem related to Li-S batteries is the occurrence (in the course of the discharge process) of sulphides of variable stoichiometry, which react with cathode reaction products, thereby decreasing the general efficiency of the battery. This problem may be solved by immobilising sulphur in a high-efficiency cathode of appropriate structure and with high electric properties.

How to improve parameters

Structures which may facilitate achievement of such parameters may be spatial Metal Organic Frameworks (MOFs) grown on bases with reduced graphene oxide (rGO) – MOF@rGO.

Such systems will efficiently bind elemental sulphur in acid-base reactions (according to Lewis theory) occurring with a metal ion coming from MOFs, which will be on the rGO base.

Interlayer spaces between the nanolayers of rGO will lessen the consequences of changes of the volume related to the charging/discharging process and loss of sulphur through blocking it in interlayer spaces. In addition, MOF@rGO are flexible, have high mechanical strength, excellent electric conductivity, large active surface and low mass of the rGO itself.

Long-lasting electricity sources

The MOGLiS project aims at developing high-efficiency cathode materials using an innovative architecture of structures MOF@rGO at the Technology Readiness Level (TRL) IV, for applications in Li-S batteries.

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The upgraded cathodes will facilitate development and then mass production of new-generation Li-S batteries, which will be able to meet the rising global demand for flexible, inexpensive and long-lasting electricity sources of high energy density, which are a key element in transition to low-emissions economy.

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Polish-Norwegian collaboration

International collaboration within the MOGLiS project among leading European centres will facilitate cooperation of battery production sectors which are leaders both in terms of technology and industry. To achieve that, a strong external consulting board has also been established, comprising experts in the field.

The MOGLiS project is done by the Warsaw University of Technology (project leader), Norwegian University of Science and Technology in Trondheim (Norway) and SINTEF organisation (Norway).

Project leader and coordinator is Professor Marek Marcinek from the Faculty of Chemistry of the Warsaw University of Technology. The Polish partner is responsible for the development and testing of cathode materials in their final form. Maciej Marczewski, PhD, DSc, from the Faculty of Chemistry of the Warsaw University of Technology, is responsible for the Polish part of the project.

The project was additionally funded in the competition organised by the international network M-ERA.NET