Range of recycling technologiesRecycling Complexity of process 'Mixing' of materials streams Amount of materials recovered Value of materials recovered Fig. 1 | The waste management hierarchy and range of recycling options. The waste management hierarchy is a concept that was developed from the Council Directive 75/442/EEC of 15 July 1975 (https://eur-lex.europa.eu/legal-content/ EN/TXT/?uri=CELEX%3A31975L0442) on waste by the Dutch politician Ad Lansink, in 1979, who presented to the Dutch parliament a simple schematic representation that has been termed 'Lansink's Ladder', ranking waste management options from the most to least environmentally desirable options.Here, that hierarchy is expanded to consider the range of battery recycling technologies. 'Prevention' means that LIBs are designed to use less-critical materials (high economic importance, but at risk of short supply) and that electric vehicles should be lighter and have smaller batteries. 'Re-use' means that electric-vehicle batteries should have a second use. 'Recycling' means that batteries should be recycled, recovering as much material as possible and preserving any structural value and quality (for example, preventing contamination). 'Recovery' means using some battery materials as energy for processes such as fuel for pyrometallurgy. Finally, 'disposal' means that no value is recovered and the waste goes to landfill.

Metal oxides, in the form of dispersed powders, have been tested as potential catalysts for the four-electron oxidation of water to 0, under photochemical conditions. The most efficient catalysts were found to be IrO,, Co,O,, RuO,, NiCo,O,, Rh,O, and Mn,O, and, in particular, high activity was observed with IrO,. Comparison of the oxide structure with its observed rate of 0, generation under standard conditions has allowed formulation of a few general requisites for an effective catalyst. Samples of iridium oxide deposited onto the surface of a second (inert) oxide were tested for their 0,-evolving capability. The efficiency of the system depended markedly upon the nature of the support. Materials that favour formation of small deposits of iridium oxide (e.g. ZnO, MgO, TiO,) are the best supports, whilst 0, production is almost completely inhibited with acidic supports. Many metal oxides can be prepared in the form of hydrates of variable composition. These materials also function as 0,-evolving catalysts, the efficiency of the process depending upon any thermal pretreatment. This finding is explained in terms of changes in structure and composition of the oxide that occur upon heating.As part of a protracted research programme, concerned with building a photosystem capable of storing solar energy via the photodissociation of water, a range of 0,-evolving catalysts has been developed. 1-6 Mostly, these catalysts have contained ruthenium dioxide in some form, and all have been prone to corrosion under high anodic bias. homogeneous,'^ colloidal5* and heterogeneou~l.~ Ru0,-based catalysts have been tested for their 0,-evolving capacities under photochemical conditions. In certain cases, quite high efficiencies have been reported. Despite such detailed studies, the poor performance of the catalyst remains as the most serious obstacle in developing a suitable anodic branch of a solar-energy storage device and, if a satisfactory catalyst is to be identified, attention should be given to materials other than RuO,. Indeed, it has been shown that Ir0,,lo Pt0210 and MnO," powders will function as heterogeneous catalysts for water oxidation in related model systems.Using a well established photochemical test system,6 we have evaluated the 0,-evolving capabilities of a range of metal oxides. These materials have been used in the form of powders suspended in aqueous solution. Most of the materials were found to be inferior to RuO, powders, but a few oxides, notably IrO,, were effective catalysts for water oxidation and demonstrated much higher levels of corrosion resistance than the catalysts used previously. Several of these oxides exist in the form of hydrates for which the 0,-evolving capability is increased upon dehydration. In order to extend the scope of the work, a series of catalysts was prepared in which IrO, was deposited onto the surface of a second (inert) oxide. By this means, the effect of the supporting agent on the 2795

Coronavirus disease 2019 , caused by severe acute respiratory syndrome coronavirus 2, has spread globally, and no proven treatments are available. Convalescent plasma therapy has been used with varying degrees of success to treat severe microbial infections for >100 years. Patients (n Z 25) with severe and/or life-threatening COVID-19 disease were enrolled at the Houston Methodist hospitals from March 28, 2020, to April 14, 2020. Patients were transfused with convalescent plasma, obtained from donors with confirmed severe acute respiratory syndrome coronavirus 2 infection who had recovered. The primary study outcome was safety, and the secondary outcome was clinical status at day 14 after transfusion. Clinical improvement was assessed on the basis of a modified World Health Organization six-point ordinal scale and laboratory parameters. Viral genome sequencing was performed on donor and recipient strains. At day 7 after transfusion with convalescent plasma, nine patients had at least a one-point improvement in clinical scale, and seven of those were discharged. By day 14 after transfusion, 19 (76%) patients had at least a one-point improvement in clinical status, and 11 were discharged. No adverse events as a result of plasma transfusion were observed. Whole genome sequencing data did not identify a strain genotype-disease severity correlation. The data indicate that administration of convalescent plasma is a safe treatment option for those with severe COVID-19 disease.