Sugar-based polymers for renewable, degradable and efficient battery electrolytes

点击翻译按钮获取中文摘要

Context of Research:As the world transitions towards a low carbon economy, storing the energy generated by intermittent renewablesources is crucial. Rechargeable lithium-based batteries are promising technologies due to their high energycapacity. However, the liquid electrolytes employed in lithium-ion batteries (LIBs) currently available on the marketpose safety issues including flammability and release of toxic products when damaged. Using a polymer doped withion salts as a Solid Polymer Electrolyte (SPE) is a safer and lightweight alternative, which has also been shown toincrease battery life. Poly(ethylene oxide) (PEO) mixed with ion salts is the most popular and researched SPE.However, it has many shortcomings including poor ionic conductivity and mechanical strength but no majoraltenatives exist.The Buchard group has previously developed a platform of functionalisable sugar-based polymers, which arehypothesised to be suitable to develop novel high-performance SPEs:1. The high oxygen content of these sugar-based polymers will promote coordination and therefore solubility of ionsalts.2. The structure and properties of these polymers can be varied to explore a large chemical space relevant to severalion mobility mechanisms.3. These polymers are renewable, (bio)degradable and non-toxic.Aims and objectives of research project:The aim of this PhD research project is to develop a range of novel SPEs based upon polymers derived from naturalsugars.The objectives of this project are: 1) Synthesise a series of sugar-based polymers targeted towards cation transport.This will be carried out using a range of established methodologies to prepare various cyclic monomers with differentlinkages and diverse functional groups. These monomers will be polymerised using controlled polymerisationtechniques and analysis of the resulting materials will be performed to establish their structure/properties relationship.2) Prepare solid polymer electroly tes by combining these polymers with ion salts via solvent casting from solution.The SPEs will be characterised with various techniques including thermogravimetric analysis and differentialscanning calorimetry. Electrochemical performance of the SPEs will be investigated by electron impedancespectroscopy to assess the SPE's suitability as a battery electrolyte material.Potential applications and benefits:The main potential application of this research is as a replacement to liquid electrolytes traditionally using incommercial lithium-ion batteries. This is beneficial as by replacing liquid electrolytes with SPEs the safety of thebatteries will be improved due to the reduced flammability and no leakage of toxic by-products if the battery isdamaged. SPEs hold great potential for the next generation of rechargeable batteries, including those based onmultivalent and abundant metal anodes (Mg, Ca). Furthermore, another benefit is that these polymers are renewable,(bio)degradable and non-toxic, which would minimise the carbon footprint of the batteries and facilitate recycling ofthe precious elements involved in their manufacture. Without legitimising a thrown-away culture, biodegradable SPEscould also find a place in short-lived devices, that are not retrieved from the environment.The second supervisor to this project is Prof. Frank Marken who has expertise in electrochemistry and will be able toprovide support in electrochemical analysis of SPEs.