Targeted recovery of metals from Thermoelectric Generators (TEGs) using chloride brines and ultrasound

Recovery of elemental copper, bismuth, tellurium, antimony and tin from Thermoelectric Generators (TEGs) is vital to recover the high content of critical metals and potential risk of environmental pollution as a result of incorrect disposal of TEGs and to enable the circular economy. In this work, aqueous choline chloride and calcium chloride hexahydrate brines were characterised and used in combination with copper(II) as an oxidising agent to leach copper and tin from TEGs. This permitted the Bi2-xSbxTe3 legs to readily separated from the ceramic substrates by filtration. It was shown that at low chloride content, surface passivation and solubility of the oxidised species was the limiting factor towards oxidation, whereas solvent viscosity (mass transport) was the limiting factor at high chloride content. The copper(II) species formed in the different brines were determined via UV-vis spectroscopy. The redox potentials of the oxidising species were found to be significantly altered by choline chloride content, but not so much by calcium chloride hexahydrate content, suggesting variation in chloride activity within the different brines. The developed approach has been shown to be a viable and scalable method to recover high value critical metals from e-waste containing TEGs

Site-selective incorporation and ligation of protein aldehydes

The incorporation of aldehyde handles into proteins, and subsequent chemical reactions thereof, is rapidly proving to be an effective way of generating homogeneous, covalently linked protein constructs that can display a vast array of functionality. In this review, we discuss methods for introducing aldehydes into target proteins, and summarise the ligation strategies for site-selective modification of proteins containing this class of functional handles

The development of advanced low cost InP based photovoltaic devices

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

ZT Optimization: An Application Focus

Significant research has been performed on the challenge of improving thermoelectric materials, with maximum peak figure of merit, ZT, the most common target. We use an approximate thermoelectric material model, matched to real materials, to demonstrate that when an application is known, average ZT is a significantly better optimization target. We quantify this difference with some examples, with one scenario showing that changing the doping to increase peak ZT by 19% can lead to a performance drop of 16%. The importance of average ZT means that the temperature at which the ZT peak occurs should be given similar weight to the value of the peak. An ideal material for an application operates across the maximum peak ZT, otherwise maximum performance occurs when the peak value is reduced in order to improve the peak position

Solid-Liquid Interdiffusion (SLID) Bonding of p-Type Skutterudite Thermoelectric Material Using Al-Ni Interlayers

Over the past few years, significant progress towards implementation of environmentally sustainable and cost-effective thermoelectric power generation has been made. However, the reliability and high-temperature stability challenges of incorporating thermoelectric materials into modules still represent a key bottleneck. Here, we demonstrate an implementation of the Solid-Liquid Interdiffusion technique used for bonding Mmy(Fe,Co)4Sb12 p-type thermoelectric material to metallic interconnect using a novel aluminium⁻nickel multi-layered system. It was found that the diffusion reaction-controlled process leads to the formation of two distinct intermetallic compounds (IMCs), Al3Ni and Al3Ni2, with a theoretical melting point higher than the initial bonding temperature. Different manufacturing parameters have also been investigated and their influence on electrical, mechanical and microstructural features of bonded components are reported here. The resulting electrical contact resistances and apparent shear strengths for components with residual aluminium were measured to be (2.8 ± 0.4) × 10−5 Ω∙cm2 and 5.1 ± 0.5 MPa and with aluminium completely transformed into Al3Ni and Al3Ni2 IMCs were (4.8 ± 0.3) × 10−5 Ω∙cm2 and 4.5 ± 0.5 MPa respectively. The behaviour and microstructural changes in the joining material have been evaluated through isothermal annealing at hot-leg working temperature to investigate the stability and evolution of the contact

Automotive power harvesting/thermoelectric applications

Legislative CO2 emission penalties and the desire to increase overall efficiency using the least expensive technology for automotive vehicles has led manufacturers to research and develop thermoelectric generators (TEGs). TEGs will play an important role in achieving a large-scale, sustainable energy solution. However, the conflicting material characteristics needed for TEGs pose a formidable challenge. The suitability and opportunities for thermoelectric devices in automotive applications are discussed, with particular emphasis on systems for electrical energy generation from exhaust gases. The significant challenges for integrating thermoelectric devices into a device for wide scale automotive deployment are outlined, including the balancing of the many different requirements for the system such as thermal management, thermoelectric materials, design and packaging constraints, etc. Some of the failure modes of thermoelectric modules in such a system are also reviewed

Fast synthesis of n-type half-heusler TiNiSn thermoelectric material

The n-type half-Heusler TiNiSn is very promising for thermoelectric applications in the medium temperature range. However, the synthesis of TiNiSn often involves long annealing times (up to several weeks) to obtain a single phase, which is a major barrier to scaling-up. In this work, TiNiSn was synthesized by a combination of arc-melting, ball-milling and spark plasma sintering. The obtained samples with diameters up to 30 mm had high-purity, high-density and fine-grains. Without the need for an annealing step, the total synthesis time was significantly shortened. Addition of Cu was used to optimize the thermoelectric properties of TiNiSn, and a maximum figure of merit of 0.6 was achieved at 773 K. The fast and scalable synthesis of TiNiSn with good thermoelectric performance presented in this work opens up the possibility of industrial scaling-up