News & Views in 2020

Dye-sensitized solar cells are promising as power-generating solar windows yet their fixed transparency prevents control of indoor lighting and temperature. Researchers now present a device that dynamically self-adjusts its optical transmittance with sunlight intensity, opening up a way to energy-efficient self-powered building façades.

Li₄Ti₅O₁₂ is a commonly used negative electrode material, but the origin of its fast rate capability has puzzled scientists for decades. Now, a facile Li-ion transport route featuring metastable intermediates is revealed to rationalize the fast-charging kinetics.

The power conversion efficiency of solar cells sensitized with colloidal quantum dots is believed to be limited by surface defects. Research now finds that photocarriers trapped at shallow defect states can actually be recovered and ultimately contribute to device efficiency.

Photocatalytic conversion of methane to ethane suffers from low yields due to poor selectivity and quantum efficiency. Now, ethane is produced by a photochemical looping strategy using a nanocomposite of titanium dioxide, phosphotungstic acid and silver cations, with selectivity of 90% and quantum efficiency of 3.5% at 362 nm.

Light-driven production of hydrogen by coupling natural photosystems or photosensitizers with hydrogen-producing catalysts has been achieved in numerous in vitro systems. Now, a recombinant in vivo system is described that generates hydrogen using a hydrogenase enzyme directly coupled to a cyanobacterial photosystem.

Microsized battery anodes such as silicon offer cost advantages over nanosized counterparts but suffer from poor cycling stability. Now, an electrolyte design is reported to enable a LiF-rich solid–electrolyte interphase that stabilizes microsized silicon over a reasonably long cycle life.

Low-cost, efficient hydrogen production via water electrolysis is expected to be an important part of a future hydrogen economy. Towards this end, new polymers with high stability are demonstrated and paired with low-cost, earth-abundant metal catalysts in alkaline membrane electrolyzers.

Hot carrier solar cells require mechanisms to dramatically reduce the rate at which carriers thermalize in semiconductors. Now, side-valley trapping of hot carriers with long decay lifetimes is shown to increase the chance of extraction of carriers while they are still hot.

In the face of more frequent long-duration power outages, utilities are looking to invest in more resilient infrastructure and solutions. A new study shows that residential customers are willing to pay for increased resilience and will spend extra to support their communities and low-income neighbours.

Understanding the activity and stability of oxygen-evolving anodes is crucial for developing better water splitting electrolysers. Researchers now show the importance of interactions between iron and hydr(oxy)oxide hosts in dynamically-stable electrocatalysts that balance dissolution and deposition of iron present in the electrolyte.

All-solid-state lithium batteries typically suffer from low coulombic efficiencies and lithium dendrite growth at high current densities. Now, a silver–carbon composite anode is demonstrated that mitigates some of these problems, even for a prototype cell with a high energy density of over 900 Wh L^–1.

In the intensive search for higher performance Li-ion cathode materials the spotlight is firmly fixed on Li-rich compounds. Now, a strategy utilizing a fluorinated, disordered LiMn₂O₄ spinel structure shows how ultra-fast Li-ion diffusion and high energy density can be achieved with Mn and O redox.

If the UK leaves the European Union single market without a suitable trade deal, then electricity trade with its European Union partners could be disrupted. New research estimates the 2030 cost of a hard electricity Brexit to Britain at €300 million per year.

Community energy projects may be pivotal in low-carbon transitions, yet little empirical evidence exists about their financing. Now, research sheds light on the financial mechanisms and performance of community energy projects in the UK.

Perovskite solar cells with an inverted configuration hold great promise for multi-junction applications, but their power conversion efficiency is low. Now, a long-chain alkylamine ligand-assisted strategy has been demonstrated to enable an efficiency of 22.34%.

Carbon capture typically relies on pressure or temperature swings for uptake and release of CO₂. Researchers now present a device exploiting electrochemistry to drive these processes in an electro-swing approach that grants flexibility for coupling to intermittent energy resources and may have broad applications for carbon capture.

Colloidal perovskite quantum dots offer potential stability advantages for solar cells over bulk perovskites but lag far behind in device efficiency. Now, a modified cation exchange method has been shown to improve the optoelectronic quality of perovskite nanocrystals, improving further the efficiency and stability of quantum dot solar cells.

International energy economic analysis frequently involves conversion of all monetary figures to a single currency, typically the US dollar. This can cause significant variation in estimation of values that change over time such as learning rates for new energy technologies.

Water management is an important aspect in the operation of alkaline exchange membrane fuel cells. Now, a lightly cross-linked norbornene polymer membrane is shown to be able to facilitate optimal water transport, leading to exceptionally high power and current density fuel cells.