Repositório do LNEG
Repositório Científico do Laboratório Nacional de Energia e Geologia
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Lithium Role in the Clean Energy Transition: Challenges and Prospects
Publication . Almeida, Joana; Pedrosa, Fátima; Plancha, Maria João; Gonçalves, Ana; Nogueira, Carlos
ABSTRACT: Global decarbonization strategies depend on the large-scale electrification of the transport sector, mainly supported by lithium-ion battery technologies. Lithium’s role in assisting low-carbon mobility has driven a fast rise in demand. This has intensified concerns regarding resource scarcity and supply chain vulnerabilities, particularly in the European Union, which remains heavily dependent on imports. The restricted availability of lithium and other critical raw materials, compounded by geopolitical tensions, poses a risk to the resilience of the clean energy transition. In this sense, the adoption of circular economy principles has emerged, emphasizing material recovery, recycling, and resource efficiency. This review provides a comprehensive analysis of lithium relevance in the energy transition, with a focus on resource trends, recovery technologies, and battery production. A systematic understanding of these trends and challenges is needed to guide future developments and ensure a secure, sustainable, and circular lithium value chain that supports the transition to clean energy systems.
SPEEK-based membranes for enhanced ion transport and chemical stability [Resumo]
Publication . Teixeira, Fatima; Teixeira, António Paulo Silva; Rangel, Carmen M.
ABSTRACT: Membranes are a key component of electrochemical devices such as fuel cells and electrolyzers. Nafion® membranes, considered the industry-standard benchmark, exhibits several performance limitations which has fostered research for better membranes.1-3 Alternative membrane improvements are driven by the need to lower production costs and improve ion transport, chemical and thermal durability along with controlling excessive swelling and gas crossover. In this work, new membranes based on poly(etheretherketone) (SPEEK) polymer were prepared by the addition of polyvinylidene fluoride (PVDF) and the incorporation of graphene oxide with bisphosphonic acid functionalities (GOBP) as a dopant. The new membranes are characterized and their properties evaluated, showing improved proton conductivity and chemical durability.
Lithium-Ion Battery Recycling by Physical Processing: Evaluation of Recovery and Metal Content in Shredding and Sieving Operations
Publication . Nogueira, Carlos; Margarido, Fernanda; Neiva Correia, Maria Joana; Pedrosa, Fátima; Plancha, Maria João; Gonçalves, Ana
ABSTRACT: Recycling of spent Li-ion batteries is essential for the sustainable management of critical raw materials for battery production. The pre-metallurgical steps, involving shredding and physical processing, are important operations for separation and concentration of the electrode powders constituting the black mass. This paper presents a laboratorial study of the shredding of pouch-type LIB cells to assess the efficiency of liberation of the powders of electrode materials, envisaging their recovery. The particle size distribution and the elemental chemical analysis of the main metals in the cathode materials (Li, Ni, Co, Mn) as well as the main contaminants (Al, Cu) allowed to assess the recovery yields and purity of the fine fraction obtained in the sieving operation. The results showed that the cell casings (aluminum laminate) were essentially present in the coarser sizes (8–10 mm). Cathode metals were mainly in the intermediate and fine fraction, both as liberated particles and as particles within Al foil (thus, not liberated). Several scenarios for separation of cathode powders were studied. The main conclusion is that, by using a separation sieve of 0.5 mm, it is possible to recover 44% of the cathode materials with low contamination of Al and Cu (with contents 0.6% and 3.7%, respectively). This is a good achievement when considering simple shredding and sieving operations. Higher recoveries would need more grinding steps and other physical processing operations.
Protic Imidazolium Ionic Liquids for Electroreduction of CO2
Publication . Messias, Sofia; Paninho, A. B.; Pires, Carolina; Rangel, Carmen M.; Martins, Rodrigo; Mendes, Manuel Joao; Branco, Luis; Machado, Ana
ABSTRACT: Protic ionic liquids characterized by permutable protons have important applications in electrochemistry. This work represents an unprecedented report of the use of such electrolytes for CO2 electroreduction (ECR) into CO at 10 bar and near room temperature (45 degrees C) on zinc electrodes. It was observed that when protic ILs are synthesized from strong acids, the competition with the hydrogen evolution reaction increases. In contrast, the use of softer acids in the synthesis significantly enhances CO production. Imidazolium-based protic ILs were chosen due to their known high CO2 solubility and consequently their potential to increase reaction productivity. The electrolytes were electrochemically characterized, their conductivities and diffusion coefficients were determined, and their performance was compared. Despite the aqueous nature of the electrolyte, remarkably, 100% Faradaic efficiencies were obtained with [HMIM][Lac] containing 50 wt % water. The performance of the aqueous protic 50 wt % [HMIM][Lac] electrolyte surpassed the performance of the non-protic 50 wt % [EMIM][OTf] electrolyte. Furthermore, among the investigated water concentrations, the maximum CO production for the protic 50 wt % [HMIM][Lac] (177 & micro;mol/cm2) is of the same order as the magnitude of 90 wt % [EMIM][OTf] (271 & micro;mol/cm2), an almost pure IL, more expensive, and less sustainable electrolyte. The non-fluorinated bio-based lactate anion concurs to the higher sustainability of the process. Hydrophilic protic ILs are thus promising as electrolytes for ECR.
Optimised photocatalytic H2 production using nanostructured low cost and sustainable photocatalysts
Publication . Esteves, M. Alexandra; Brites, Maria João de Sousa; Capelo, Anabela; Pinheiro, Carla I.C.; Lanham, Ana; Ramos, Diana; Pedro, Guilherme
ABSTRACT: The SPECTRUM project aims to design, develop, prototype, and test lab-scale solar collectors that effectively utilise the entire solar spectrum to cogenerate heat, electricity and hydrogen. SPECTRUM Work package 1 is dedicated to the optimization of the photocatalytic process of industrial wastewater (IWW) treatment and hydrogen generation and is divided in four tasks. This deliverable D1.3 provides an account of the activities carried out in Task 1.3, “Optimization of Photocatalytic H₂ Production Process at Laboratory Scale,” as well as the results achieved during its duration. The photocatalysts developed in Task 1.2, “Development of nanostructured low cost and sustainable photocatalyst”, were tested for hydrogen production in a slurry type batch reactor using UV radiation as light source. In these preliminary assays, synthetic aqueous solutions containing ethanol or glycerol as sacrificial agent (SA) were used to test the performance of a first series of copper decorated TiO2 nanoparticles (NP) photocatalysts. A comprehensive series of experiments enabled the selection of the most effective photocatalyst, Cu-decorated TiO2 nanoparticles with 6 weight % of copper (Cu/TNP-6). This photocatalyst was then utilized with aqueous solutions of ethanol or glycerol to optimize three key operational parameters — pH, photocatalyst concentration, and sacrificial agent concentration. The same methodology was subsequently applied to evaluate the performance of two additional copper-based photocatalyst sets developed in Task 1.2: copper-decorated TiO₂ nanotubes and copper/biochar-decorated TiO₂ nanoparticles.