New developments in main group chemistry for application in modern battery technology

Student thesis: Doctoral Thesis

Abstract

The first results chapter discusses results unrelated to magnesium batteries, however, thetechniques used were similar to those utilised in other results chapter. Arylmethyl anions allow alkali-metals to bind in a σ-fashion to the lateral carbanionic centre or a π-fashion to the aryl ring or in between these extremities, with the trend towards π bonding increasing on descending group 1. Here we review known alkali metal structures of diphenylmethane, fluorene, 2-benzylpyridine and 4-benzylpyridine. Next, we synthesise Li, Na, K monomers of these diarylmethyls using polydentate donors PMDETA or Me6TREN to remove competing oligomerizing interactions, studying the effect that two aromatic rings has on negative charge (de)localisation via NMR spectroscopy, X-ray crystallographic analysis and DFT studies. For magnesium batteries, the ‘All Phenyl Complex’ (APC) has been shown to be one of the foremost electrolyte complexes, with the active species considered to be [Mg2Cl3·6THF]+[AlPh4]-. Originally synthesised through the reaction of PhMgCl and AlCl3 in THF, this hasshown to be a low atom economic route and instead an alternative method of combining Ph2Mg and half an equivalent of AlCl3 has been shown to yield the same active species but with a higher atom economy. Based on this knowledge, a range of R2Mg species have been developed and further reacted with AlCl3 to produce an array of [Mg2Cl3·6THF]+[AlR4]- complexes which could potentially be superior electrolytes. These have been analysed through X-ray crystallography and NMR spectroscopy and have been tested electrochemically, with DFT calculations also performed where appropriate.
Date of Award24 Aug 2023
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsUniversity of Strathclyde
SupervisorStuart Robertson (Supervisor) & Robert Mulvey (Supervisor)

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