Energy science and technology

  • Article
    | Open Access

    Harvesting incident photons with energy below the bandgap may lead to highly efficient solar cells. By introducing InAs quantum dots at the hetero-interface, Asahiet al. achieve efficient two step photon up-conversion resulting in additional photocurrent and very high external quantum efficiency.

    • Shigeo Asahi
    • , Haruyuki Teranishi
    •  & Takashi Kita
  • Article
    | Open Access

    Thermoelectric modules can generate electricity directly from heat and have applications to waste heat-energy conversion. Here Zhouet al. have fabricated a thermoelectric module based on an air-stable n-type single-walled carbon nanotube sheet which can reach a high power factor of 1500 μWm−1K−2.

    • Wenbin Zhou
    • , Qingxia Fan
    •  & Sishen Xie
  • Article
    | Open Access

    Ideal energy storage technologies should be efficient, safe and cost-effective. Here, the authors make progress by using dissolved sodium metal in a solution of biphenyl and ethers as a liquid anode for rechargeable sodium beta-alumina batteries.

    • Juezhi Yu
    • , Yong-Sheng Hu
    •  & Liquan Chen
  • Article
    | Open Access

    Manganese oxide cathodes in alkaline solutions combine low cost and high capacity for energy storage, but it has been challenging to combine high capacity and stable cycling in this system. Here authors demonstrate reversible, high-capacity cycling when copper additives are introduced and investigate the transformations involved.

    • Gautam G. Yadav
    • , Joshua W. Gallaway
    •  & Sanjoy Banerjee
  • Article
    | Open Access

    The commercialization of solar cells based on hybrid perovskites requires challenges of device stability and scalable production to be addressed. Ronget al. report ambient-processed printable mesoscopic perovskite solar cells with a lifetime of over 130 days in ambient air with 30% relative humidity.

    • Yaoguang Rong
    • , Xiaomeng Hou
    •  & Hongwei Han
  • Article
    | Open Access

    Using low dose transmission electron microscopy, Rothmann, Li, Zhuet al. report direct evidence for twin domains in tetragonal CH3NH3PbI3perovskite. The relevant scale and transition temperature of these twin domains could have implications for perovskite solar cells.

    • Mathias Uller Rothmann
    • , Wei Li
    •  & Yi-Bing Cheng
  • Article
    | Open Access

    Two-dimensional solids are of interest for energy storage due to their large accessible surface area, enabling rapid charge/discharge. Here, the authors quantify the point defects in oxide nanosheets, demonstrating that intentional introduction of charged point defects improves the charge storage behaviour.

    • Peng Gao
    • , Peter Metz
    •  & Scott T. Misture
  • Article
    | Open Access

    Water is believed to undermine the performance of aprotic lithium–air batteries. However, the authors here disclose different battery chemistry, showing that both lithium ions and protons are involved in the battery reactions in the presence of water, leading to an unprecedented dynamic product.

    • Yun Guang Zhu
    • , Qi Liu
    •  & Qing Wang
  • Article
    | Open Access

    Slow cooling of hot charge carriers in lead halide perovskite could be used in photovoltaics devices. Here, Yanget al. study hot carrier dynamics by transient absorption spectroscopy. They relate the phonon bottleneck to the up-conversion of low-energy phonons, facilitated by the presence of organic cations.

    • Jianfeng Yang
    • , Xiaoming Wen
    •  & Gavin Conibeer
  • Article
    | Open Access

    Cycling-induced fracture can limit conditions for stable operation for various lithium-ion electrode materials. Here, the authors characterize fracture in nickel-manganese-cobalt oxide microscopically and provide evidence for dislocation-assisted, intragranular fracture operating above a critical voltage threshold.

    • Pengfei Yan
    • , Jianming Zheng
    •  & Chong-Min Wang
  • Article
    | Open Access

    A large proportion of methane emissions from natural gas production sites are released by a fraction of high-emitting sources. Here, using Monte Carlo simulations, the authors reveal that super-emitters occur due to abnormal process conditions, explaining component and site-based inventory discrepancies.

    • Daniel Zavala-Araiza
    • , Ramón A Alvarez
    •  & Steven P. Hamburg
  • Article
    | Open Access

    Rechargeable magnesium batteries suffer from slow solid-state Mg2+diffusion in the intercalation cathode. Here the authors show magnesium/iodine chemistry in which the liquid–solid two-phase reaction leads to increased rate capabilities by overcoming the sluggish kinetics.

    • Huajun Tian
    • , Tao Gao
    •  & Chunsheng Wang
  • Article
    | Open Access

    Photosynthesis uses only a limited range of solar radiation. Here, Graysonet al. genetically incorporated the yellow fluorescent protein (YFP) chromophore into a bacterial photosystem, and show that energy harvested by reaction centre–YFP complexes can augment photosynthesis in vivo.

    • Katie J. Grayson
    • , Kaitlyn M. Faries
    •  & C. Neil Hunter
  • Article
    | Open Access

    Lithium-based batteries employing silicon anodes and sulfur cathodes are promising for combining low cost and high capacity, but have been limited in terms of cycling stability. Here authors present cycling and characterization data supporting beneficial synergies between a selenium disulfide cathode and a silicon anode.

    • KwangSup Eom
    • , Jung Tae Lee
    •  & Thomas F. Fuller
  • Article
    | Open Access

    Carbon nanotube yarns with high loadings of pseudocapacitive material are desirable, e.g., for emerging wearable technologies. Here authors make biscrolled yarns with high loadings of MnO2nanoparticles confined in carbon nanotube galleries, demonstrating very high linear and areal capacitances.

    • Changsoon Choi
    • , Kang Min Kim
    •  & Seon Jeong Kim
  • Article
    | Open Access

    Metal oxide semiconductors are promising photoelectrode materials for solar water splitting but their efficiency needs to be improved. Here, the authors report a hetero-type dual photoelectrode strategy in which two photoanodes of different band gaps are connected in parallel for extended light harvesting.

    • Jin Hyun Kim
    • , Ji-Wook Jang
    •  & Jae Sung Lee
  • Article
    | Open Access

    Radiative cooling relies on the atmosphere’s transparency window. Here the authors achieve up to 42 °C drops in temperature for low thermal loads under diffuse sunlight by improving the selectivity of the emissivity and the thermal management of their devices.

    • Zhen Chen
    • , Linxiao Zhu
    •  & Shanhui Fan
  • Article
    | Open Access

    Hydrogen evolution by water electrolysis is a promising route to 'green energy', but efficiency is still an issue. Here, the authors make mixed organic/inorganic hierarchical nanostructures with high hydrogen evolution activity, identifying synergic effects in the material contributing to enhanced efficiency.

    • Giovanni Valenti
    • , Alessandro Boni
    •  & Francesco Paolucci
  • Article
    | Open Access

    The spin Seebeck effect enables thermal-to-electrical energy conversion but the power generated in thin films remains low. Here, Boonaet al. use composites of ferromagnetic conductors containing noble metal nanoparticles to show that the effect can enhance the transverse thermopower of bulk materials.

    • Stephen R. Boona
    • , Koen Vandaele
    •  & Joseph P. Heremans
  • Article
    | Open Access

    While the photovoltaic industry aims to achieve cleaner energy production, it consumes energy and emits greenhouse gases during production and deployment. Here, Louwenet al. show that the industry has likely already reached break-even points for both greenhouse gases emissions and electricity consumption.

    • Atse Louwen
    • , Wilfried G. J. H. M. van Sark
    •  & Ruud E. I. Schropp
  • Article
    | Open Access

    Theoretical limiting efficiencies play a critical role in determining technological viability and expectations for device prototypes. Here, the authors present a unified framework for photoelectrochemical device performance through which previous limiting efficiencies can be understood and contextualized.

    • Katherine T. Fountaine
    • , Hans Joachim Lewerenz
    •  & Harry A. Atwater
  • Article
    | Open Access

    Early stellarator designs suffered from high particle losses, an issue that can be addressed by optimization of the coils. Here the authors measure the magnetic field lines in the Wendelstein 7-X stellarator, confirming that the complicated design of the superconducting coils has been realized successfully.

    • T. Sunn Pedersen
    • , M. Otte
    •  & Sandor Zoletnik
  • Article
    | Open Access

    Piezoelectricity in diphenylalanine peptide nanotubes (PNTs) suggests an avenue towards green piezoelectric devices. Here the authors show ‘smart’ PNTs whose polarization can be controlled with an electric field, and a resultant power generator which harvests biomechanical energy with high power density.

    • Vu Nguyen
    • , Ren Zhu
    •  & Rusen Yang
  • Article
    | Open Access

    Hyperaccumulation can allow facile enrichment of metal ions in halophytic plants. Here, the authors use the effect to convert plant structures into hierarchical carbon/metal-oxide nanocomposites and demonstrate the structures as battery electrodes combining high power density and excellent cycling stability.

    • Jian Zhu
    • , Yu Shan
    •  & Xiangfeng Duan
  • Article
    | Open Access

    Rechargeable aqueous electrochemical energy storage is a promising technology but suffers from a narrow potential window. Here the authors report a surface hydroxylated Mn5O8pseudocapacitor electrode with bivalence structure that expands the potential window to deliver high energy and power performance.

    • Xiaoqiang Shan
    • , Daniel S. Charles
    •  & Xiaowei Teng
  • Article
    | Open Access

    Flexible materials for harvesting and storing energy are desirable for wearable electronics, but efficiency is still an issue. Here, the authors demonstrate a flexible and weavable ribbon which integrates a solar cell and supercapacitor via a shared electrode for efficient energy harvesting and storage.

    • Chao Li
    • , Md. Monirul Islam
    •  & Jayan Thomas
  • Article
    | Open Access

    Thermoelectric devices are often rigid and do not adapt conformally to surfaces. Here, Park et al. prepare a Bi2Te3-based thermoelectric paint, containing a Sb2Te3chalcogenidometalate additive, that can be paint-brushed onto curved surfaces and form thermoelectric modules with good efficiencies.

    • Sung Hoon Park
    • , Seungki Jo
    •  & Jae Sung Son
  • Article
    | Open Access

    Improving the stability of perovskite solar cells remains crucial. Here, Ahn et al. show that trapped charges at grain boundaries induce the dissociation of the perovskite compound in the presence of moisture, and explain why degradation is irreversible under illumination and reversible in the dark.

    • Namyoung Ahn
    • , Kwisung Kwak
    •  & Mansoo Choi
  • Article
    | Open Access

    In order to be practical for large-scale deployment, the cost of solar hydrogen generation must be significantly reduced. Here, the authors employ a triple-junction solar cell with two series connected polymer electrolyte membrane electrolysers to achieve solar to hydrogen efficiency of 30%.

    • Jieyang Jia
    • , Linsey C. Seitz
    •  & Thomas F. Jaramillo
  • Article
    | Open Access

    Fe-N/C catalysts show surprising activity towards oxygen reduction in fuel cells. However, there is significant uncertainty as to the structure of the active site. Here, the authors quantify the number and turnover frequency of the active sites by reversibly blocking those sites with nitrite (NO2¯).

    • Daniel Malko
    • , Anthony Kucernak
    •  & Thiago Lopes
  • Article
    | Open Access

    In organic photovoltaics, electron acceptors are developed to replace fullerenes, and new donors need to be designed to match these acceptors. Here, the authors show that a polymer with strong temperature dependent aggregation and intentionally reduced crystallinity matches non-fullerene acceptors.

    • Zhengke Li
    • , Kui Jiang
    •  & He Yan
  • Article
    | Open Access

    High performance CdTe thin film solar cells typically require a chloride activation treatment. Here, Majoret al. show that the main effect of the most effective chloride-based treatments is chloride accumulation at grain boundaries and that it results in improved open circuit voltages.

    • J. D. Major
    • , M. Al Turkestani
    •  & K. Durose
  • Article
    | Open Access

    In photovoltaics, sub-band gap energy photons can be harvested using up-conversion strategies. Here, the authors show that the thermally enhanced up-converted photoluminescence results in enhanced energy conversion, for an accessible temperature range and with a broad range of incident photon energy.

    • Assaf Manor
    • , Nimrod Kruger
    •  & Carmel Rotschild
  • Article
    | Open Access

    Direct measurement of electron-phonon interactions at the single-mode level has been a challenge. Here, Liaoet al. use a three-pulse photoacoustic spectroscopy technique to investigate the damping of a single sub-terahertz coherent phonon mode by photo-excited free charge carriers in silicon at room temperature.

    • Bolin Liao
    • , A. A. Maznev
    •  & Gang Chen
  • Article
    | Open Access

    Multiple exciton generation could help limit thermalization losses in solar cells, but the efficiency of the process is still limited. Here, the authors show by atomistic calculations that type-II interfaces in nanostructures along with a change in exciton cooling rate favour multiple exciton generation.

    • Hagai Eshet
    • , Roi Baer
    •  & Eran Rabani
  • Article
    | Open Access

    Perovskite solar cells reach high efficiencies but their stability remains a challenge. Here, Bai et al. functionalize the fullerene-based transport layer with hydrophobic and crosslinkable molecules to prepare devices reaching 19% efficiency and degrading by 10% over a month in ambient conditions.

    • Yang Bai
    • , Qingfeng Dong
    •  & Jinsong Huang
  • Article
    | Open Access

    The energy harvesting potential of triboelectric nanogenerators is currently limited by their output power. Here, the authors design a triboelectric nanogenerator inspired by lightning generation, featuring an electric double layer that delivers impressive charge separation and electric potential.

    • Jinsung Chun
    • , Byeong Uk Ye
    •  & Jeong Min Baik
  • Article
    | Open Access

    Zeolite crystal with porous structure is predicted to be a good membrane material for water purification, but experiments show water uptake orders of magnitude smaller than the theory. Here, Fasano et al. attribute this disagreement to the additional diffusion resistance induced by surface defects.

    • Matteo Fasano
    • , Thomas Humplik
    •  & Pietro Asinari
  • Article
    | Open Access

    Harvesting bio-mechanical energy is a promising route to powering wearable electronics, however design obstacles remain. Here the authors report on a triboelectric nanogenerator with optimized materials and design that can sustainably power an electronic watch and fitness tracker solely by human motion.

    • Jie Wang
    • , Shengming Li
    •  & Zhong Lin Wang
  • Article
    | Open Access

    Tomographic imaging of graphite-based anodes is challenging due to weak X-ray attenuation contrast. Here, the authors use operando propagation-based phase contrast tomography and digital volume correlation to study the electrochemical activity and microstructural dynamics in (silicon−) graphite electrodes.

    • Patrick Pietsch
    • , Daniel Westhoff
    •  & Vanessa Wood