Historically, the growth of energy consumption has fuelled human development, but this approach is no longer socially and environmentally sustainable. Recent analyses suggest that some individual countries have responded to this issue successfully by decoupling Total Primary Energy Supply from human development increase. However, globalisation and international trade have allowed high-income countries to outsource industrial production to lower income countries, thereby increasingly relying on foreign energy use to satisfy their own consumption of goods and services. Accounting for the import of embodied energy in goods and services, this study proposes an alternative estimation of the Decoupling Index based on the Total Primary Energy Footprint rather than Total Primary Energy Supply. An analysis of 126 countries over the years 2000-2014 demonstrates that previous studies based on energy supply highly overestimated decoupling. Footprint-based results, on the other hand, show an overall decrease of the Decoupling Index for most countries (93 out of 126). There is a reduction of the number of both absolutely decoupled countries (from 40 to 27) and relatively decoupled countries (from 29 to 17), and an increase of coupled countries (from 55 to 80). Furthermore, the study shows that decoupling is not a phenomenon characterising only high-income countries due to improvements in energy efficiency, but is also occurring in countries with low Human Development Index and low energy consumption. Finally, six exemplary countries have been identified, which were able to maintain a continuous decoupling trend. From these exemplary countries, lessons have been identified in order to boost the necessary global decoupling of energy consumption and achieved welfare.

Lithium-sulfur (Li–S) batteries present a great potential to displace current energy storage chemistries thanks to their energy density that goes far beyond conventional batteries. To promote the development of greener Li–S batteries, closing the existing gap between the quantification of the potential environmental impacts associated with Li–S cathodes and their performance is required. Herein we show a comparative analysis of the life cycle environmental impacts of five Li–S battery cathodes with high sulfur loadings (1.5–15 mg·cm −2 ) through life cycle assessment (LCA) methodology and cradle-to-gate boundary. Depending on the selected battery, the environmental impact can be reduced by a factor up to 5. LCA results from Li–S batteries are compared with the conventional lithium ion battery from Ecoinvent 3.6 database, showing a decreased environmental impact per kWh of storage capacity. A predominant role of the electrolyte on the environmental burdens associated with the use of Li–S batteries was also found. Sensitivity analysis shows that the specific impacts can be reduced by up to 70% by limiting the amount of used electrolyte. Overall, this manuscript emphasizes the potential of Li–S technology to develop environmentally benign batteries aimed at replacing existing energy storage systems.

energy storage (EES) systems can store and deliver on-demand renewable power, smoothing the intermittency associated with wind and solar energy when installed in large renewable-energy plants [3,4] Electricity generation systems based on renewable resources present an environmentally and socioeconomically more sustainable alternative to those based on fossil fuels. [5] Ensuring a steady energy supply can accelerate the transition to a lower carbon economy, approaching toward the emission reductions of 30% by 2030 to meet the goals of Paris Agreement.Thanks to their high energy density and long cycling stability, [6] lithium ion batteries (LIBs) are dominant in the portable electronics and electric vehicle (EV) markets. However, the implementation of LIBs as stationary grid storage has been constrained so far due to the fact that LIBs present several sustainability issues. The use of large quantities of scarce and toxic cathode materials (lithium, cobalt, or nickel) inevitably increases their environmental burdens. [7] Environmentally speaking, sodium ion batteries (NIBs) are emerging as a potential alternative to LIBs given the natural availability of sodium. [8] NIBs are cost-effective, offer acceptable energy densities and enable the use of bio-derived electrodes, [9][10][11] so they have a prominent position to next-generation batteries replacing LIBs. As for LIBs, a completely inert, oxygen Aqueous zinc ion batteries (AZIBs) are gaining widespread scientific and industrial attention thanks to their safety and potential environmental sustainability in comparison with other battery chemistries relying on organic electrolytes. AZIBs are good candidates for sustainable stationary storage, covering household energy needs or smoothing the intermittency associated with wind and solar energy. In spite of their potential as a sustainable energy storage technology, the study of their environmental repercussions remains unexplored. The environmental impacts associated with the fabrication of AZIBs are quantified using a cradle-to-gate life cycle assessment (LCA) methodology. Six laboratory-scale battery designs offering high delivered capacity, energy density and operating lifespan are selected. The contribution of different battery components to eighteen environmental impact indicators is shown. An average value of 45.1 kg CO 2 equiv per 1 kWh is obtained considering the metallic Zn anode, the cathode, the separator, the aqueous electrolyte and the electricity required for cell assembly. AZIBs are environmentally competitive with lithium-ion, lithium-oxygen, lithium-sulfur, and sodium-ion battery technologies and are attractive from a Circular Economy viewpoint given the potential of renewable materials as separators and the high recycling rates of electrodes. The obtained results prove the suitability of zinc ion batteries as a sustainable stationary energy storage solution.

Aprotic lithium−oxygen (Li−O 2 ) batteries are a prominent example of ultrahigh energy density batteries. Although Li−O 2 batteries hold a great potential for large-scale electrochemical energy storage and electric vehicles, their implementation is lagging due to the complex reactions occurring at the cathode. Great effort has been applied to find practical cathodes through the incorporation of different materials acting as catalysts. Here we tap into the quantification of the environmental footprint of seven highperformance Li−O 2 batteries. The batteries were standardized to feed a 60 kWh electric vehicle. Life cycle assessment (LCA) methodology is applied to determine and compare how different batteries and respective components contribute to environmental footprints, categorized in 18 groups. To get a bigger picture, results are compared with the environmental burdens of a reference lithium ion battery, reference sodium ion battery, and the average value of lithium−sulfur batteries. Overall, Li−O 2 batteries present lower environmental burdens in 9 impact categories, with similar impacts in 5 categories in comparison with lithium−sulfur and lithium ion batteries. With an average value of 55.76 kg•CO 2 equiv in Global Warming Potential for the whole Li−O 2 battery, the cathode is the major contributor, with a relative weight of 44.5%. These results provide a road map to enable the practical design of sustainable aprotic Li−O 2 batteries within a circular economy perspective.

The global demand for lithium-ion batteries (LIBs) has witnessed an unprecedented increase during the last decade and is expected to do so in the future. Although the service life of batteries could be expanded using Circular Economy approaches such as repair or remanufacture, batteries will inevitably become a huge waste stream as electric vehicles gain popularity. Battery recycling reintroduces end-of-life materials back into the economic cycle and prevents landfill scenarios. The reclamation of materials from spent batteries in general, and cathodes in particular, reduces the pressure over finite critical raw materials such as cobalt, nickel, lithium, or manganese and avoids severe heavy metal contamination issues associated with battery disposal. To establish a sustainable battery-recycling industry, the environmental impact assessment of cathode-recycling approaches is urgently needed. Accordingly, a life-cycle assessment methodology is applied to quantify and compare the environmental impacts of nine hydrometallurgical laboratory-scale LIB cathode-recycling processes in 18 impact indicators such as global warming potential. The LiNi 1/3 Co 1/3 Mn 1/3 O 2 cathode is selected given its predominant market share among electric vehicles. Hydrometallurgical recycling approaches based on inorganic acid-leaching (hydrochloric, sulfuric, and phosphoric acids), inorganic alkali-leaching (ammonia/sodium sulfite), organic leachates (citric, formic, or lactic acids), and bioleaching processes are analyzed. Scaling up the recycling to 1 kg cathode, global warming values from 25.1 to 95.2 kg•CO 2 -equiv per 1 kg of recycled cathode are obtained. The processes based on HCl and H 2 SO 4 /H 2 O 2 and the autotrophic bio-leaching process are preferred to lower greenhouse gas emissions and toxicity-and resource-related potential impacts. The choice of chemicals, the energy consumption, and more importantly, material efficiency emerge as the cornerstones to achieve environmentally sustainable processes. A sensitivity analysis demonstrates the potential to reduce the impacts by transitioning to a renewable energy mix, reaching a global warming value of 5.01 kg•CO 2 -equiv•kg cathode −1 . These results provide guidance toward further process optimization through eco-design approaches, securing the long-term sustainability of LIBs.