Smith et al explore deep eutectic solvents (DESs) and their applications, focusing on the properties of DESs, metal processing applications, and synthesis applications.
Recycling is always seen as an end-of-pipe process returning as much material as possible into a circular economy. There is a growing school of thought that suggests product design should be an ...important step in the recycling process. While this review is aimed specifically at one technological product, it contains facets that are applicable to the recycling of any complex product. Decarbonisation of energy production necessitates a proliferation of efficient electrical storage and a significant proportion of this, particularly in automotive propulsion, will use lithium ion batteries. The scale of the projected electric vehicle market means that a circular economy model needs to be established while the scale of end-of-life product is still manageable to prevent a build-up of hazardous waste. This critical review investigates the issues of lithium ion battery recycling and discusses the aspects of pack, module and cell design that can simplify battery dismantling and recycling. It highlights not only Green aspects of elemental recovery, but also technoeconomic features which may govern the appropriate direction for recycling. It also shows that as cell design changes, the approach to recycling can become more efficient.
Product design is an important factor which can control the efficiency and economics of a recycling flowsheet.
Processing of metals and metal oxides using ionic liquids ABBOTT, Andrew P; FRISCH, Gero; HARTLEY, Jennifer ...
Green chemistry : an international journal and green chemistry resource : GC,
01/2011, Letnik:
13, Številka:
3
Journal Article
Recenzirano
Hydrometallurgy lies at the heart of many industrial processes and is the source of a large volume of aqueous waste. Treating dilute streams of acidic and basic by-products is both energy and ...chemical intensive, and is one of the largest sources of metal-based emissions into the environment. Over the past decade, numerous studies have been made into the use of ionic liquids for metal dissolution, extraction and recovery. This article critically reviews the potential efficacy of these methods and signposts the areas where further research is needed.
•Aniline electropolymerisation shown to not be solely controlled by pH in DESs.•Dynamic light scattering shows that the monomer is in a colloidal phase for all systems where electropolymerisation ...occurs.•Size of PANI particles similar to dimensions of colloidal dispersed phase.•Aniline emulsions tend to form when water is added to DESs.
The electropolymerisation of aniline is a well-studied and often used technology. While the mechanism has been investigated in a variety of media these have all concentrated on understanding the process on a molecular level. Anomalies in the electropolymerisation of aniline in four deep eutectic solvents, DESs, using urea, ethylene glycol, glycerol and oxalic acids as hydrogen bond donors with choline chloride led to an investigation of the aniline phase behaviour. It was only with oxalic acid that polymerisation was achieved and adjusting the pH of the other DESs using sulphuric acid did not enable polymer formation suggesting that pH was not the only factor enabling polymer growth. When 10 wt% water was added, polymers could be grown in all the DESs despite negligible change in solution pH. Dynamic light scattering showed that polymer only formed in systems where aniline formed an emulsion. Scanning electron microscopy, SEM and atomic force microscopy, AFM showed that the polyaniline films were formed of an agglomeration of small particles of the same dimensions as the dispersed monomer phase in solution. This suggests that the droplets of the monomer arrive at the electrode surface where they polymerise. This provides the first evidence that polyaniline grows by an emulsion polymerisation mechanism even in aqueous solutions.
Display omitted
Display omitted
•Facile electro-deposition of bright Ni is possible from DES electrolytes at elevated temp. and high concentration.•Harder Ni deposits are obtained from DES than from aqueous ...electrolytes.•Similar deposition rates are measured despite the higher viscosity of the DES.•High temp. speciation of Ni2+ in DES determines morphology of deposit.•Ni deposition in DES shows a levelling effect when compared to Ni plating in aqueous electrolytes.
Metal electrodeposition using ionic liquid electrolytes and deep eutectic solvents is now well known but to our knowledge for electrolytic deposition of metals such as nickel no direct comparison has thus far been drawn between deposition using aqueous solutions and DES under otherwise identical conditions. In the current study it is shown that nickel deposition can be carried out with similar deposition rates in aqueous and ionic media despite the significant differences in viscosity and conductivity. It is, however, shown that in ionic media the morphology of the deposits is markedly different from that achieved using a Watts nickel bath and that one aspect of these differences manifests itself in significant increase in the coating hardness. It is proposed that the observed morphology differences occur due to the variations of nickel speciation in each electrolyte environment.
Although mineral oils are commonly used as lubricants their emission particularly in marine environments can cause significant impact. In the current study the properties of water miscible deep ...eutectic solvents and ionic liquids are compared with a typical mineral base oil to ascertain their efficacy for potential marine lubricants. The environmental compatibility of some of the liquids, particularly choline chloride and glycerol, makes it an interesting potential base lubricant. Surprisingly some DESs showed very low corrosion rates with steel, nickel and aluminium even when the liquids contained water. This is a surprising result given that the chloride ion concentration is approximately 5 mol dm
−3
.
Water miscible ionic liquids and deep eutectic solvents have useful properties that make them suitable for lubricants especially in marine environments.
Organic and inorganic additives are often added to nickel electroplating solutions to improve surface finish, reduce roughness and promote uniform surface morphology of the coatings. Such additives ...are usually small molecules and often referred to as brighteners or levellers. However, there have been limited investigations into the effect of such additives on electrodeposition from ionic liquids (ILs) and deep eutectic solvents (DESs). Here we study the effect of four additives on electrolytic nickel plating from an ethyleneglycol based DES; these are nicotinic acid (NA), methylnicotinate (MN), 5,5-dimethylhydantoin (DMH) and boric acid (BA). The additives show limited influence on the bulk Ni(
ii
) speciation but have significant influence on the electrochemical behaviour of Ni deposition. Small concentrations (
ca.
15 mM) of NA and MN show inhibition of Ni(
ii
) reduction whereas high concentrations of DMH and BA are required for a modest difference in behaviour from the additive free system. NA and MN also show that they significantly alter the nucleation and growth mechanism when compared to the additive free system and those with DMH and BA. Each of the additive systems had the effect of producing brighter and flatter bulk electrodeposits with increased coating hardness but XRD shows that NA and MN direct crystal growth to the 111 orientation whereas DMH and BA direct crystal growth to the 220 orientation.
Small molecule organic additives produce smooth, bright, adherent and hard nickel coatings during electrodeposition in a deep eutectic solvent. We present a detailed study.
Decarbonisation of energy will rely heavily, at least initially, on the use of lithium ion batteries for automotive transportation. The projected volumes of batteries necessitate the development of ...fast and efficient recycling protocols. Current methods are based on either hydrometallurgical or pyrometallurgical methods. The development of efficient separation techniques of waste lithium ion batteries into processable waste streams is needed to reduce material loss during recycling. Here we show a rapid and simple method for removing the active material from composite electrodes using high powered ultrasound in a continuous flow process. Cavitation at the electrode interface enables rapid and selective breaking of the adhesive bond, enabling an electrode to be delaminated in a matter of seconds. This enables the amount of material that can be processed in a given time and volume to be increased by a factor of approximately 100. It also produces a material of higher purity and value that can potentially be directly recycled into new electrodes.
Electric vehicle battery electrodes are delaminated ultra-fast using high-powered ultrasound, separating active materials from the foil current collectors.
Eutectic mixtures of zinc chloride and donor molecules such as urea and acetamide are described and it is proposed that these constitute a new class of ionic liquids. FAB‐MS analysis shows that the ...liquids are made up of metal‐containing anions and cations in which the donor is coordinated to the cation. Data on the viscosity, conductivity, density, phase behaviour and surface tension are presented and these are shown to be significantly different to other related ionic liquids that incorporate quaternary ammonium salts. The conductivity and viscosity are comparable with other ionic liquids and the data fit well to the Hole theory model recently proposed.
Zinc chloride can disproportionate to give ZnCl3− (right‐hand side) and ZnCl+ when mixed with suitable donor molecules, for example, acetamide, urea or ethylene glycol. This gives rise to a new class of ionic liquids, such as depicted on the left‐hand side (ZnCl(urea)+).
Here we describe for the first time the electrolytic deposition of copper and copper composites from a solution of the metal chloride salt in either urea-choline chloride, or ethylene glycol-choline ...chloride based eutectics. We show that the deposition kinetics and thermodynamics are quite unlike those in aqueous solution under comparable conditions and that the copper ion complexation is also different. The mechanism of copper nucleation is studied using chronoamperometry and it is shown that progressive nucleation leads to a bright nano-structured deposit. In contrast, instantaneous nucleation, at lower concentrations of copper ions, leads to a dull deposit. This work also pioneers the use of the electrochemical quartz crystal microbalance (EQCM) to monitor both current efficiency and the inclusion of inert particulates into the copper coatings. This technique allows the first in situ quantification or particulate inclusion. It was found that the composition of composite material was strongly dependent on the amount of species suspended in solution. It was also shown that the majority of material was dragged onto the surface rather than settling on to it. The distribution of the composite material was found to be even throughout the coating. This technology is important because it facilitates deposition of bright copper coatings without co-ligands such as cyanide. The incorporation of micron-sized particulates into ionic liquids has resulted, in one case, in a decrease in viscosity. This observation is both unusual and surprising; we explain this here in terms of an increase in the free volume of the liquid and local solvent perturbation.
PDF
