Lead acid batteries (LABs) can deliver high power, offer robustness, and ease to produce with low maintenance cost. Due to this fact LABS are still the mainstream of the energy storage over other alternative choices. These days, the amount of waste lead acid batteries (WLABs) has undeniably increased due to the expansion of the automotive sector. End-of-life lead disposal has become the major concern. The significant number of WLABs have drawn attention and the challenge is how to recycling the waste properly and efficiently since conventional recycle routes both consume massive energy and release strong acid waste.
This thesis addresses the problem by using a greener approach which has been proposed recently. Deep eutectic solvents (DESs) can eliminate the high heat applied, toxic lead soot and concentrated acid. They serve as media for metal extraction and deposition with properties of high solubility of metal salts and wider electropotential window over the aqueous solution.
With the aim to recycle WLABs, the fundamental properties and electrochemical behaviour of choline chloride-based DESs of varying HBD composition and their reaction with different lead salts (PbO, PbCO3, PbO2, and PbCl2) were carried out. Thereafter, reline became the solution of choice for lead electrodeposition due to its wide operating range and high solubility for metal. Various parameters that would effect on physicochemical properties and electrochemical behaviour were studied, aiming to optimise the performance. It was found that deposited lead is dependent to mass transport, speciation, applied potential and double layer structure. Furthermore, water doping was exploited to enhance the physicochemical behaviour. 20 wt% H2O reline both with and without PbO powder were studied. The impacts of this aqueous modulation have been investigated; viscosity, conductivity, electropotential window (EPW) and lead solubility as a function of temperature.