Advances, challenges, and environmental impacts in metal-air battery electrolytes

Efficient energy storage technologies are vital in the current efforts towards decarbonisation. Batteries, as one of the most versatile electrochemical energy storage systems, have the potential to shape the transition from the current climate crisis scenario to a carbon neutral and sustainable future. In particular, metal-air batteries are gaining scientific and industrial interest as promising contenders to the ubiquitous lithium-ion batteries. The electrolyte plays a critical role in metal-air batteries as it determines the battery performance, its safety and the operating lifespan. The low-density, ease of processing, good thermal and electrochemical stability, mechanically stiff but ductile character, electrically insulating properties and tailor-made chemistry make polymers singularly interesting to be applied as a separator/liquid electrolyte pair, gel-electrolytes or solid-electrolytes. Accordingly, in this work the current bottlenecks and challenges in metal-air batteries are presented, with particular emphasis on the electrolyte design. The implementation of aqueous liquid electrolytes, organic liquid electrolytes, polymer membranes soaked in liquid electrolytes, gel-like electrolytes and solid-state electrolytes is discussed and the environmental impacts associated with metal-air batteries are analysed within a Circular Economy perspective. We expect this work can guide future efforts in the development of potentially sustainable next generation metal-air batteries

Polimero biodegradagarrietan oinarrituriko material nanokonposatuak: Poli (L-laktida)/karbono nanotutu konpositearen kasua

Egungo gizarteak geroz eta aurrerapen zientifiko-teknologiko berritzaileagoak eskatzen ditu bere premiak asetu ahal izateko. Eskakizun hauei konponbidea emateko nanoteknologia deritzon esparruan buru-belarri dihardute zientzialariek. Zalantzarik gabe, materialen zientzia eta ingeniaritzaren ezagutza arloan, ikerketa aukera berriak agertu dira berriki lortu diren tamaina oso txikiko zuntz nanometrikoen eraketari esker. Nanomaterial guztien artean, karbono nanotutuak (KNT) dira material berrien garapenerako arreta handien piztu duen materiala. Lan honetan, proposatzen da etorkizun oparoa duen polimero biobateragarri eta biodegradagarri nagusienetako bat, Poli(L-laktida) (PLLA), izaera nanometrikodun zuntzez (KNTez) sendotzea; horrela, material nanoegituratuak lortu eta propietate hobetuak dituzten material berriak sortuko dira. Biomaterial nanoegituratu hauek kimika, biologia, fisika, ingen iaritza eta materialen zientziaren ikuspegitik aztertuak eta aplikatuak izateko etorkizun zirraragarria eskaintzen dute. Horrela, material nanokonposatuen inguruko orokortasunak azaldu ondoren, propietate eta aplikazio espezifikoetan arituko gara

Environmental Impact Assessment of Chitin Nanofibril and Nanocrystal Isolation from Fungi, Shrimp Shells, and Crab Shells

Chitin nanoparticles are responsible for the outstanding mechanical properties found in the exoskeletons of crustaceans and are finding applications in many scientific and technological fields. Following a Circular Economy approach, diverse biomass wastes can be valorized to be reintroduced back into the economic cycle while preventing biowaste landfill upon isolation of chitin nanoparticles. Novel environmentally sustainable paths over the conventional chitin nanoparticle extraction involving harsh acid-hydrolysis treatments from crustacean shells have been recently proposed. In particular, fungi emerge as an attractive alternative provided the demineralization process with acids such as HCl is circumvented. In spite of this recognized virtue, no works have quantified the environmental impacts of these processes. The life-cycle assessment methodology is applied to close this gap and quantify the cradle-to-gate impacts of chitin nanofibril extraction from fungi. The results are compared to conventional chitin nanocrystal hydrolytic isolation processes from shrimp shells, chitin powder, and crab shells, together with sulfuric-acid-induced hydrolysis of microcrystalline cellulose to cellulose nanocrystals. Eighteen impact indicators are analyzed scaling-up laboratory quantities into processes treating 1 kg of biowastes. A global warming potential value of 18.5 kg center dot CO2-equiv per 1 kg of chitin nanofibrils is obtained, well below the 906.8, 105.2, 543.5, and 177.9 kg CO2- equiv center dot kg-1 values obtained for chitin nanocrystals from shrimp shells, chitin powder, crab shells, and cellulose nanocrystals, respectively. A sensitivity analysis shows a 10.1-62.6% impact decrease to a minimum value of 14.7 kg CO2-equiv center dot kg-1 for chitin nanofibril isolation from fungi considering 95% recirculation of the solvent/NaOH, highlighting the environmentally sustainable character of chitin nanofibril extraction from fungi. The potential application of chitin nanoparticles into environmentally sustainable materials and devices is explored. These results provide novel cues for the environmentally friendly synthesis of nanochitin, guiding the implementation of sustainable approaches in the field of biomass nanoparticles.The authors are grateful for the financial support from the 2021 Euskampus Missions 1.0. Programme granted by Euskampus Fundazioa and the University of the Basque Country (Convocatoria de ayudas a grupos de investigacion GIU21/010) . The authors also acknowledge the Open Access funding provided by the UPV/EHU

Environmental Impact Assessment of Solid Polymer Electrolytes for Solid-State Lithium Batteries

Solid-state batteries play a pivotal role in the next-generation batteries as they satisfy the stringent safety requirements for stationary or electric vehicle applications. Notable efforts are devoted to the competitive design of solid polymer electrolytes (SPEs) acting as both the electrolyte and the separator. Although particular efforts to attain acceptable ionic conductivities and wide electrochemical stability widows are carried out, the environmental sustainability is largely neglected. To address this gap, here the cradle-to-gate environmental impacts of the most representative SPEs using life cycle assessment (LCA) are quantified. Raw material extraction and electrolyte fabrication are considered. Global warming potential values of 0.37–10.64 kg CO2 equiv. gelectrolyte −1 are achieved, where PEO/LiTFSI presents the lower environmental burdens. A minor role of the polymer fraction on the total impacts is observed, with a maximum CO2 footprint share of 0.61%. Following ecodesign approaches, a sensitivity analysis is performed to simulate industrial-scale fabrication processes and explore environmentally friendlier scenarios. The electrochemical performance of SPEs is further analyzed into Li/LiFePO4 solid lithium metal battery cell configuration. Overall, these results are aimed to guide the ecologically sustainable design of SPEs and facilitate the implementation of next-generation sustainable batteries.The authors gratefully acknowledge support from Siemens Gamesa (Students4Sustainability Grant) and 4GUNE (Clúster de Ingeniería, Ciencia y Tecnología de Euskadi). The authors are also grateful for the Open Access funding provided by the University of Basque Country (UPV/EHU)

Optimum operational lifespan of household appliances considering manufacturing and use stage improvements via life cycle assessment

To lessen the residential sector environmental burdens from the energy consumption of household appliances, notable efforts have been directed to replace existing energy-consuming appliances by new energy-efficient equipment. However, less attention has focused to understand the optimum operating period of households so reduced greenhouse gas emissions can be achieved. Conventional household appliances should be preferably replaced with new designs featuring improved energy efficient models, along with reduced environmental burdens associated with the manufacturing of the new products. Such studies, to the best of our knowledge, have not been extensively investigated. To address this gap, the global warming potential during the life cycle of three representative household appliances, a microwave oven, a dishwasher and a washing machine is analyzed using a cradle-to-grave life cycle assessment. To provide guidelines towards impact reduction, the current situation and four new scenarios focused on material efficiency, recycled material, renewable electricity and responsible consumption are analyzed. Depending on the scenario, impacts of 84-261, 317-1330, and 533-1375 kg.CO2 eq/lifetime are obtained for a microwave, a dishwasher and a washing machine, respectively. Balancing energy efficiency and life- time when replacing a class A appliance, operating periods of 3.4-30, 2.7-26.2 and 4.6- 33.9 years for microwaves, dishwashers, and washing machines, render the lowest CO2 footprint. These results may assist manufacturers, policymakers and citizens to promote environmentally sustainable production and consumption patterns. (C)22 The Authors. Published by Elsevier Ltd on behalf of Institution of Chemical Engineers.The authors are grateful for the support provided through the Basque Government (IT-1365-19) and the University of the Basque Country (GIC-18/22) grants

Beyond ecodesign, internationalized markets enhance the global warming potential in the wood furniture sector

Circular Economy principles encourage the implementation of bio-based and renewable materials over non-renewable technical counterparts. Wood-based materials can effectively address finite resource depletion and the accumulation of non-biodegradable waste into terrestrial and marine environments. In this context, the furniture industry has long relied on the use of wood for manufacture goods. However, the use of renewable materials is not directly translated into sustainable consumer goods. Accordingly, this work analyzes the life cycle environmental impacts of an eco-designed and locally-manufactured wooden bunk bed and compares local and international market scenarios to understand its cradle-to-grave environmental footprint. Using primary data, the life cycle assessment (LCA) methodology is followed to quantify and compare the environmental impacts of a currently commercially available wooden bunk bed over alternative scenarios. To facilitate future comparison, 1 kg of furniture is used as a functional unit. The cradle-to-grave system boundaries are established according to the reference "Furniture, except seats and mattresses" Product Category Rule. The upstream, core and downstream life-cycle stages are considered, and the environmental impacts are presented into eight different categories. To provide the bigger picture, obtained results are compared with literature. A cradle-to-grave CO2-eq footprint of 1.71 kg per kg of an already eco-designed bunk bed is obtained, 15.1% below average traditional furniture. The downstream stage contributes to the 58.3% of the total greenhouse gas emissions, while the upstream and core phases present a share of 26.2% and 15.5%, respectively. Such a large contribution of the downstream phase originates from the transportation to the final customer (82.6% of this phase). For upstream and core phases, plywood production (53.1% share during the upstream) and electricity consumption (75.1% share during the core) are the main hotspots. Furthermore, this work quantifies the global warming potential of current inter-nationalized wood furniture markets. Local furniture sale can reduce the CO2 emissions of the wooden bunk bed by 40%. Instead, selling the bed abroad involves a CO2 emission increase of 59%, while raw material importation enhances the impacts by 39-45%. The adoption of local production and consumption patterns emerge the most effective measures to reduce the environmental impacts of the furniture industry as the purchase of an overseas manufactured wood bunk increases the emissions by 79%. This research aims not only to bring light in the scientific community in LCA calculations but also help producers and consumers in the transition towards more sustainable consumption and production patterns in the wooden furniture market.The authors are grateful for the assistance provided through the Basque Government (IT-1365-19) and the University of the Basque Country (GIC-18/22; Convocatoria de ayudas a grupos de investigacion GIU21/010) grants. The authors also acknowledge the funds from the University of the Basque Country for the Open Access. Authors are also thankful to Muebles LUFE for collaborating with us and providing all the necessary primary data for this work

Transient Rechargeable Battery with a High Lithium Transport Number Cellulosic Separator

Transient batteries play a pivotal role in the development of fully autonomous transient devices, which are designed to degrade after a period of stable operation. Here, a new transient separator-electrolyte pair is introduced for lithium ion batteries. Cellulose nanocrystals (CNCs) are selectively located onto the nanopores of polyvinyl alcohol membranes, providing mobile ions to interact with the liquid electrolyte. After lithiation of CNCs, membranes with electrolyte uptake of 510 wt%, ionic conductivities of 3.077 mS center dot cm(-1), electrochemical stability of 5.5 V versus Li/Li+, and high Li+ transport numbers are achieved. Using an organic electrolyte, the separators enable stable Li metal deposition with no dendrite growth, delivering 94 mAh center dot g(-1) in Li/LiFePO4 cells at 100 mA center dot g(-1) after 200 cycles. To make the separator-electrolyte pair transient and non-toxic, the organic electrolyte is replaced by a biocompatible ionic liquid. As a proof of concept, a fully transient Li/V2O5 cell is assembled, delivering 55 mAh center dot g(-1) after 200 cycles at 100 mA center dot g(-1). Thanks to the reversible Li plating/stripping, dendrite growth suppression, capacity retention, and degradability, these materials hold a bright future in the uptake of circular economy concepts applied to the energy storage field.The authors gratefully acknowledge financial support from ETH Zurich (ETH Research Grant ETH-45 18-1). The authors thank Medicell Membranes Ltd. for kindly providing Visking dialysis membranes. The authors acknowledge support from the Scientific Center for Optical and Electron Microscopy (ScopeM) of ETH Zurich. The authors also thank Dr. Dipan Kundu for helpful discussions on transport number

Cytotoxicity and Inflammatory Effects of Chitin Nanofibrils Isolated from Fungi

Fungal nanochitin can assist the transition from the linear fossil-based economy to a circular biobased economy given its environmental benefits over conventional crustacean-nanochitin. Its real-world implementation requires carefully assessing its toxicity so that unwanted human health and environmental issues are avoided. Accordingly, the cytotoxicity and inflammatory effects of chitin nanofibrils (ChNFs) from white mushroom is assessed. ChNFs are few nanometers in diameter, with a 75.8% N-acetylation degree, a crystallinity of 59.1%, and present a 44:56 chitin/glucan weight ratio. Studies are conducted for aqueous colloidal ChNF dispersions (0–5 mg·mL–1) and free-standing films having physically entangled ChNFs. Aqueous dispersions of chitin nanocrystals (ChNCs) isolated via hydrochloric acid hydrolysis of α-chitin powder are also evaluated for comparison. Cytotoxicity studies conducted in human fibroblasts (MRC-5 cells) and murine brain microglia (BV-2 cells) reveal a comparatively safer behavior over related biobased nanomaterials. However, a strong inflammatory response was observed when BV-2 cells were cultured in the presence of colloidal ChNFs. These novel cytotoxicity and inflammatory studies shed light on the potential of fungal ChNFs for biomedical applications.E.L. acknowledges the funds from the “2021 Euskampus Missions 1.0. Programme” granted by Euskampus Fundazioa and from the University of the Basque Country (Convocatoria de Ayudas a Grupos de Investigación GIU21/010). The authors also acknowledge the Open Access funding provided by the University of Basque Country (UPV/EHU). A.L. is thankful for funds from the Basque Government, Department of Education (IT-1766-22). C.B.A. acknowledges the predoctoral grant from the UPV/EHU. Maria Angela Motta and Dr. Upashi Goswami are acknowledged for their support in cell culture

Environmental Impacts of Graphite Recycling from Spent Lithium-Ion Batteries Based on Life Cycle Assessment

[EN]With the emergence of portable electronics and electric vehicle adoption, the last decade has witnessed an increasing fabrication of lithium-ion batteries (LIBs). The future development of LIBs is threatened by the limited reserves of virgin materials, while the inadequate management of spent batteries endangers environmental and human health. According to the Circular Economy principles aiming at reintroducing end-of-life materials back into the economic cycle, further attention should be directed to the development and implementation of battery recycling processes. To enable sustainable paths for graphite recovery, the environmental footprint of state-of-the-art graphite recycling through life cycle assessment is analyzed quantifying the contribution of nine recycling methods combining pyrometallurgical and hydrometallurgical approaches to indicators such as global warming, ozone layer depletion potential, ecotoxicity, eutrophication, or acidification. Laboratory-scale recycling is scaled up into pilot-scale processes able to treat 100 kg of spent graphite. With values ranging from 0.53 to 9.76 kg.CO2 equiv. per 1 kg of graphite, energy consumption and waste acid generation are the main environmental drivers. A sensitivity analysis demonstrates a 20-73% impact reduction by limiting to one-fourth the amount of H2SO4. Combined processes involving hydrometallurgy and pyrometallurgy give environmentally preferable results. The electrochemical performance of regenerated graphite is also compared with virgin battery-grade graphite. This work provides cues boosting the environmentally sustainable recyclThe authors are grateful for Open Access funding provided by the University of Basque Country (UPV/EHU)