News & Views in 2018

Efficient conversion of low-grade heat into useful power is a challenge. A new approach using magnetocaloric materials and a pretzel-like magnetic field topology offers a simple way of generating electrical power from heat with improved efficiency.

Multilateral development banks, such as the World Bank, have been encouraging countries to invest more in green-energy technologies. Analysis of project data suggests their own renewable energy portfolios have also grown in step.

Perceptions of energy use and potential savings are rife with systematic and problematic errors. Now research shows that these misperceptions are more important predictors than actual savings for consumer acceptance of a demand-side response programme, potentially limiting the effectiveness of such programmes for both utilities and consumers.

Aluminium−graphite batteries can reversibly store AlCl₄^– ions at their cathodes, but the large consumption of electrolytes reduces their specific energy. Here a cathode based on redox-active triangular organic molecules is shown to be able to take up AlCl₂⁺, offering hope towards complete Al-ion storage.

Ammonia holds promise as a clean energy carrier, but its synthesis requires high pressures and large production scales that are ill-matched to renewable, decentralized energy production. Now, researchers use metal imides to mediate ammonia production in a chemical looping process that operates under mild conditions.

Two-terminal all-perovskite tandem structures are promising as low-cost yet highly efficient solar cells, but their development is limited by the poor quality of the low bandgap absorber layer. Now, a processing method has been shown to enable the production of uniform, thick tin–lead perovskite layers, which translate into improved photovoltaic parameters.

Cryogenic-electron microscopy is rapidly transforming battery research. Now, this powerful technique has been used to identify lithium hydride as a surprising culprit behind Li-ion battery failure.

The recent German energy transition has been taken as an exemplary case for a new, decentralized and renewable-energy-based approach to energy policy worldwide. New comparative research shows, however, that its national-level interpretations outside of Germany vary considerably, reflecting country-specific contextualization and visions of a good society.

Semi-artificial photosynthesis offers advantages over purely natural or synthetic routes to producing chemicals from solar energy, but devices based on it have remained elusive. Now, researchers couple a dye-sensitized photoanode with natural components to generate H₂ photoelectrochemically from water without additional bias.

Solar home systems are seen as a quick and effective way to relieve people from energy poverty in sub-Saharan Africa. A new study shows that such systems can be more than an interim solution towards achieving SDG7 as they become cheaper than grid electricity while providing the same or better levels of reliability.

Combining biofuel synthesis with petrorefinery operations may provide efficiency benefits, but procedures to do so are not yet well-established. Now, researchers describe a two-phase catalytic scheme for production of 10% bio-enriched gasoline by directly using petroleum fractions in the catalytic processing of (hemi)cellulose.

Battery temperature needs to be regulated in operation. Now, a shape memory alloy-based thermal regulator is shown to be able to automatically switch between thermally insulating and conducting states depending on temperature, demonstrating a new paradigm for thermal management of batteries.

Photocatalytic water splitting is a route to clean H₂, but approaches based on hybrid semiconductor–metal nanoparticles often rely on sacrificial reagents to complete the oxidation half of the overall reaction. New research uses CdS nanocrystals modified with metallic and molecular co-catalysts to simultaneously produce H₂ and O₂ from water using visible light.

Electricity production has traditionally required extensive water use, so growing economies such as China are expected to increase their freshwater withdrawal and consumption to meet growing electricity demand. Research shows, however, that through restructuring the electricity sector and increasing efficiency, China may have broken this coupling.

The concept of energy security is multifaceted, and can cover a number of seemingly distinct energy- and climate-related risks. Now, research shows that public opinion about energy security reflects the geographic variation in these risks, such that cross-country differences in public concern are explained by national energy context and indicators.

Passivating contact technologies have enabled new record efficiencies in crystalline silicon photovoltaics, but they are still far from implementation into mainstream manufacturing. Now, a passivation approach has been shown that exploits the quick firing step currently employed in industrial fabrication by rethinking material design.

The German Energiewende is an ambitious project, but the expansion of renewables needed to achieve its goals is expensive. Now, research shows that consumers would accept higher levies to finance renewables if exemption policies were abolished, forcing industries to pay their fair share.

Renewable portfolio standards in the United States are widely recognized as a significant state-level instrument to catalyse growth in renewables. Comprehensive analysis now shows that the effectiveness of these standards depends on their stringency, with more demanding standards leading to higher renewable penetration.

Harsh operating conditions, such as high temperatures, hinder the grid-scale application of liquid metal batteries (LMBs). Now, their operating temperature is shown to be substantially lowered thanks to a lithium-ion-conducting solid-state electrolyte.

Voltage fade has been a major barrier to the commercialization of a series of high-energy-density battery electrodes for more than a decade. It is now re-examined with advanced characterization techniques, which find its origin is correlated to oxygen activities.