Novel materials for high capacity sulphur based batteries
Doktorsavhandling, 2018

Batteries have become a vital part of our everyday lives and are used in a wide range of portable electronic devices (e.g. mobile phones, laptops, toy, and power tools). With the increased problems of environmental pollution, due to the use of fossil fuels for electric energy and transportation, there is an increased need for high capacity batteries for load levelling in renewable energy systems (wind, solar, tidal, etc.) and for electric vehicles. Li-ion batteries are currently very successful in portable applications. However, the specific capacity of current systems (< 250 mAh/g, < 120 Wh/kg), typically based on lithiated graphite anodes and metal oxide cathodes, is not sufficient for large-scale applications. In addition, there is also a need to improve battery technology in terms of price and sustainability concerning the raw of materials used. This has motivated research on next generation battery technology based on other chemistries.
 
One of the most promising chemistries for next generation batteries is based on the conversion of sulphur. As an example, the theoretical discharge capacity of a lithium-sulphur cell is 1675 mAh/g or 2500 Wh/kg. Sulphur can also be coupled to sodium or used in the form a metal sulphide (e.g. FeS2), still with superior capacity compared to Li-ion technology. Considering that the active material, sulphur, has a low cost and is abundant brings also the potential for a low cost and sustainable technology. However, even though sulphur-based batteries are very promising their theoretical capacity has so far not been realised in practice in a cell with long cycle life and high charge/discharge efficiency.
 
In this thesis, I present new materials concepts aiming to enable next generation high capacity batteries based on the conversion of sulphur. The main target has been to improve the capacity, but the materials used have also good perspective in terms of sustainability and price. A key to improve the properties has been to tailor materials on the nanoscale. One example is the fibre-based materials prepared by electrospinning. These include carbon structures for high capacity and high rate electrodes as well as gel-polymer electrolyte membranes. The results presented in the thesis show that high discharge capacity and good cycle performance can be achieved with the new materials concepts. The functional mechanisms behind the concepts is discussed and the role of different material aspects is revealed.

gel electrolyte

lithium-sulphur battery

catholyte

next generation batteries

electrospinning

Lecture Hall Kollektorn, MC2 building
Opponent: Professor Thomas Wågberg, Department of Physics Umeå University, Sweden

Författare

Du Hyun Lim

Chalmers, Fysik, Kondenserade materiens fysik

D.H. Lim, M. Agostini, J.H. Ahn, A. Matic, electrospun nano-fibre membrane as gel-based electrolyte for room temperature Na/S batteries

A. K. Haridas, J.E. Lim, D.H. Lim, J.K. Kim, K.K. Cho, A. Matic, J.H. Ahn, Electrospun core-shell nanofiber web as high performance cathode for iron disulfide-based rechargeable lithium batteries

M. Agostini, D.H. Lim, S. Brutti, N. Lindahl, J.H. Ahn, B. Scrosati, A. Matic, Free-standing 3-D sponged nano-fibre electrodes for ultrahigh-rate energy storage devices

M. Agostini, D.H. Lim, M. Sadd, J.Y. Hwang, S. Brutti, J.H. Ahn, Y.K. Sun, A. Matic, Towards low cost and high energy lithium sulfur batteries through the use of a tailored fluorine-free Li2S8 based electrolyte

A major factor for future development is the generation and distribution of energy, which is required for transportation, industrial and commercial activities, buildings and infrastructure, water distribution, and food production. Urban areas have experienced dramatic growth and development over the last two decades, which has led to high-energy consumption. Around 80% of the global energy supply is provided by fossil fuels and only 9% by renewable energy sources. The unrestrained use of non-renewable fossil fuels is significantly contributing towards global warming as well as significantly polluting the environment.
 
In order to challenge this energy crisis and to ensure a healthy, viable, and environmentally sound future, the world demands innovation in the energy sector. The best replacement for fossil fuels is the use of renewable energy resources - such as wind, solar, geothermal, tidal - which are constantly replenished and will never run out. However, their intrinsic issue of be unable to provide a continuous energy supply limits the prolific utilization of renewable energy systems. Therefore, a massive power storage system is required, such as rechargeable batteries, pumping-up power generation, flywheels, and compressed gas energy storage. Out of these listed methods, rechargeable batteries show many advantages in terms of high energy density and flexibility in design and low environmental impact if installations. Rechargeable batteries are already play a vital role in our everyday lives, by powering our smartphones, laptops, and power tools. Many of these are powered by Li-ion batteries which is currently the technology with the highest energy for a certain volume or weight, i.e. a small battery can power a device for a long time. However, for large scale applications, like electric cars, the performance is not good enough. In addition, from a sustainability point of view, the technology can also be improved, since today expensive and environmentally unfriendly metals are used. Thus, there is a large interest to develop new battery technologies.
 
One of the most promising technologies for future batteries for large scale energy storage is based on the conversion chemistry of sulphur. In theory a car powered by a sulphur-based battery could drive more than 1000 km on one charge. In addition, sulphur is abundant and cheap, the use of this technology would contribute to sustainable development within the energy storage market. Several advancements have been made, but still the technology is not ready to be applied in practical applications. To take this step, new materials with tailored properties need to be developed and this has been the topic of my thesis. By using materials modified from the very small length scales of atoms and up to improve the performance. Based on the results from my work several routes can be identified which can be taken to realise the potential of sulphur-based batteries, which both have very good performance and use environmentally friendly and low cost materials.

Drivkrafter

Hållbar utveckling

Innovation och entreprenörskap

Styrkeområden

Nanovetenskap och nanoteknik

Energi

Materialvetenskap

Ämneskategorier

Materialkemi

Annan kemiteknik

Energisystem

Infrastruktur

Chalmers materialanalyslaboratorium

ISBN

978-91-7597-732-4

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4413

Utgivare

Chalmers tekniska högskola

Lecture Hall Kollektorn, MC2 building

Opponent: Professor Thomas Wågberg, Department of Physics Umeå University, Sweden

Mer information

Senast uppdaterat

2018-05-17