The shift towards an energy mix with more renewable sources have resulted in massive quantities of solar photovoltaics being installed over the worls. This is a growing electronic waste stream that needs to be planned for. Present appropaches to solar recycling involve high-temperature burning for separation and release of the PV cells for metal recovery processes. However, such processes can release gaseous by-products that can cause serious health and environmental issues as well as deprioritises the recovery of pure silicon. This talk will cover our group's efforts in developing new extraction techniques that eschew burning as well as incorporate green solvents. Through an incorporation of such novel techniques along with hydrometallurgy, we demonstrate separation of glass, extraction of the various metallic elements such as Ag, Cu and Al as well as silicon at good purity levels. Our efforts in upcycling the extracted elements into other products such as thermoelectrics as well as battery anodes will also be described. 

The current models of production and consumption are no longer deemed adequate because of the inefficient use of resources (especially energy) and its environmental consequences. To sustainably meet the growing energy demands of the world, a substantial increase in the deployment of photovoltaic and energy storage technologies is needed. Dye-sensitized solar cells (DSCs) have the potential to provide a viable source of renewable energy to help decarbonize our economy and power wearable devices. With their exceptional performance in diffused light under indoor conditions, DSCs remain competitive for powering the next digital revolution forming the internet of things (IoT). They can also be interfaced with storage materials to enable a new generation of energy storable solar cells. While this is all encouraging, with the increase in the number of deployed devices arises the need to evaluate their end-of-life, transition to a resource efficient circular economy. In this talk, I will evaluate each component of a dye-solar cell from an environmental point of view. I will present the various material design routes being developed to enable a sustainable approach both during fabrication and as readily ‘refurbishable/upgradable’ devices, leveraging the ability to replace dyes and electrolytes repeatedly with no observable loss in functionality over many product generations. My talk will identify features which are conducive to circular economy and identify barriers to resource efficiency for these technologies and suggest some potential solutions and priority areas for future research.

References: 1. R. G. Charles, M. L. Davies and P. Douglas, "Third generation photovoltaics — Early intervention for circular economy and a sustainable future," 2016 Electronics Goes Green 2016+ (EGG), Berlin, Germany, 2016, pp. 1-8, doi: 10.1109/EGG.2016.7829820.

IRENA estimates that 70 million tonnes PV waste will have been generated by 2050. Furthermore, we are already seeing challenges in the supply chains of critical materials for renewable energy and electronics. Emerging solar technologies involve printable devices which have low embedded energy and are fully recyclable at the end of their life. Using recycled materials in these devices could lead to further enery savings and reduced environmental impact, as well as providing a versatile, low cost technology for clean energy. We present the outcomes of a proof-of-concept to provide data to assess the potential for printable electronic, electrochemical and photovoltaic devices using waste materials. Carbon black has numerous applications, but production leads to 2.4 kg CO₂ emissions per kg virgin carbon black. Our project seeks to identify opportunities for the recycled carbon black as a higher-value product in electronic and electrochemical devices, such as printable photovoltaics. Most current research into printable solar cells using the triple mesoscopic stack configuration uses commercial carbon inks which is based on virgin carbon black. We have developed conductive inks from recovered carbon black from waste tyres, tested them in devices (indoors and outdoors) and then shown that the device itself can be regenerated and re-used.

In this talk I will present our latest discoveries in converting bio and plastc waste into high value chemicals and H2 via electrooxidation reactions including catalyst design, mechanism and upscale . We will target prescursors such as ethylene glycol or glycerol.  I will also talk about upgrading plastic into carbon composites for Na ion batteries. In particular I will talk about some high energy density C/Sn  cpmpsotes and the alloying mechanism of Na with Sn.

In both cases i will talk about in operando techiques development such as XAS or XRD-PDF. Initial results on LCA will also be presented from the perspective of economic viability and   environmental footprint.

Givcen the importance of net zero technologies, this talk will provide insights into waste utilisation towads high value added products.  Products such as glycolic acid or lactic  acid deriving from such processes can be used in  cosmentic and renwable plastic . H2 represents a huge market and  technology, where I still have a lot  to learn

Recycling processes for lithium-ion batteries (LIBs) have been developed to remove chemical compounds from these batteries for secondary uses, as well as resynthesizing cathode material using direct or short-loop recycling, for use in cathodes of fresh batteries. The reason for extracting compounds from the cathode of discarded LIBs is that they are composed of high value and critical minerals such as Li, Co, Ni and Mn. In particular the cathodes with compositions such as LiCoO₂, LiNi_yMn_zCo_xO₂, and LiMn₂O₄ are important to evaluate for reclamation of these metals and re-use. It is known from the literature that end-of-life LiNi_yMn_zCo_xO₂ contains around 15 to 20% less lithium than fresh cathode and therefore cannot be directly reuse without further lithiation. It is a challenge to return this end of life and recovered black mass, containing NMC materials to form that can be reused in a new cell. In this work we describe a direct recycling route for the discarded NMC532 using a low cost, and facile relithiation process. The cathode material was extracted from a disassembled end of life or scrap NMC vs graphite pouch cell, and then delaminated from aluminium using a 3.5M NaOH solution that selectively dissolved the Al foil. The recovered powder was analyzed by XRF, XRD, CHNS and ICP-OES techniques. After characterization, solid state relithiation was carried out with the lithium source LiOH at 700 °C and the product of this reaction was analyzed again using the above techniques and evaluated electrochemically.

The aviation industry is responsible for 2% of the total GHG emissions and 10% of the fuel consumption worldwide, with a predicted market growth of 3.7% a year. It is expected that a large portion of the current global fleet will continue to be operational until 2040-2050 calling for the development of drop-in alternatives based on sustainable resources [1].

Significant research efforts have been devoted to identifying routes to produce liquid fuels from CO₂ and H₂ leveraging the Fisher-Tropsch (FT) synthesis. One option is to feed CO₂ and H₂ in a reverse water gas shift reactor (RWGS) and use the resulting syngas in a traditional FT process [2]. The limitations of this approach are: (i) the RWGS reactor operates at high temperatures (600-1000 °C); and (ii) the FT reactor produces a significant amount of wax, a mixture of heavy hydrocarbons that requires additional upgrading units, such as a hydrocracking (HC) reactor to improve the yield of liquid fuels. The direct hydrogenation of CO₂ to liquid fuels in a single step is more appealing, but usually the formation of short chain hydrocarbons is favoured [3]. Yao et al. (2020) [4] synthesized a novel Mn-Fe-K based catalyst capable of converting CO₂ and H₂ with excellent yield and selectivity towards liquid hydrocarbons in the jet fuel range (C8–C16) and minimal wax production.

In this work, we carry out a techno-economic analysis and life-cycle assessment (LCA) of two SAF production processes: a one-step process (1sFT) based on the above-mentioned catalyst; and a two-step process (2sFT) based on the work of [2]. Both processes are fed with CO2 from direct air capture (DAC) and green H2. 1sFT and 2sFT are simulated at scale using Aspen HYSYS to evaluate their economic performances and obtain inventories for the LCA. The environmental assessment is conducted in SIMAPRO 9.3, using Ecoinvent 3.8 Cut-Off database for the background process inventories. The fuel obtained from 1sFT and 2sFT is compared against the fossil-based alternative considering different environmental KPIs, as for SAF to be truly sustainable the reduction is GHG emission should not be associated with high collateral ecological damage, a problem often referred to as burden shifting. ReCiPe2016 is used as life-cycle impact assessment method [5] and GWP100 is evaluated alongside the monetized endpoint impacts to human health, ecosystem quality and resource scarcity. 

Our results show that the one-step process is superior both in economic and environmental terms to the two steps process, due to a lower capital cost, higher selectivity towards liquid hydrocarbons and lower energy requirements. On a well-to-wake basis the 1sFT process is predicted to reduce GHG emissions by 75% and the 2sFT process by 58%. The analysis of the endpoint environmental impacts confirms a better environmental performance of the synthetic fuels compared to the fossil counterpart, with the 1sFT outperforming the 2sFT by a larger extent, with 1sFT and 2sFT having a total externality cost 44% and 22% lower that the fossil fuel, respectively. At current CO2 and H2 prices the productions cost of low-carbon synthetic fuels is predicted to be 6-8 times higher than fossil-based aviation fuels, which is in agreement with the literature, and a combination of feedstock cost reduction and policy intervention (e.g. carbon taxation) is necessary for synthetic fuels to become cost competitive.