• Energy Research

Abstract Background: Understanding how warming temperatures are influencing biomasses in the world’s forests is necessary for quantifying future global C (carbon) budgets. A temperature-driven decrease in future C stocks could dangerously strengthen climate change. Empirical methods for studying the temperature response of forests have important limitations, and modelling is needed to provide another perspective. We modelled current and future AGB (old-growth above-ground biomass) in humid lowland areas of the world by dividing GPP (gross primary productivity) and a measure of energy needed to support a given about of biomass called here MCB (maintenance cost per unit biomass). Results: Based on the modelling, we predict a temperature-driven increase in both GPP and MCB, except in the tropics, where GPP will decrease. Their ratio, and therefore also ABG, is expected to decrease in all other regions except the boreal. The AGB is expected to decrease 41% in the tropics and 29% globally.Conclusions: The estimated drops in AGB are dramatic. However, we did not include the fertilisation effects of increasing CO2 (carbon dioxide) and N (nitrogen) that potentially mitigate the temperature-caused drop in AGB.

AbstractSingle‐layer fuel cells (SLFCs) are the product of recent advances in low‐temperature solid‐oxide fuel cell (SOFC) research and development. Conventional three‐layer materials comprising an anode, an electrolyte, and a cathode have been replaced by one‐layer materials that can integrate all of the functions of fuel cell anodes, electrolytes, and cathodes into one function. Excellent performance, simple technology, and ultra‐low cost have increased the potential of SLFCs for commercialization. Therefore, methods should be developed to scale up this innovative and advanced SOFC technology for engineering use and further commercial applications. This work reports the scaling up of an SLFC through powder material preparation, pulp preparation and tape casting, cold‐press shaping, hot pressing, and final surface reduction to fabricate 6 cm×6 cm engineering cells with an active area of 25 cm2. Each SLFC delivers approximately 10 W of power at 525–550 °C. The performance of the device is comparable with or even better than that of conventional SOFCs. A maximum output power of 12.0 W (0.48 W cm−2) is obtained from the 6 cm×6 cm SLFC at 550 °C. This study develops a scaling‐up technology that uses tape casting and hot pressing to enhance the commercial uses of SLFC.

Abstract A novel fuel-to-electricity conversion technology resembling a fuel cell has been developed based on the perovskite solar cell principle using a perovskite, e.g. La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3− δ and an ionic nanocomposite material as a core functional layer, sandwiched between n- and p-conducting layers. The conversion process makes use of semiconductor energy bands and junctions properties. The physical properties of the junction and alignment of the semiconductor energy band allow for direct ion transport and prevent internal electronic short-circuiting, while at the same time avoiding losses at distinct electrolyte/electrode interfaces typical to conventional fuel cells. The new device achieved a stable power output of 1080 mWcm −2 at 550 °C in converting hydrogen fuel into electricity.

Abstract All-oxide solar cells are presently attracting extensive research interest due to their excellent stability, low-cost and non-toxicity. However, the band gap of metal oxides is lack of effective optimization and results in poor photovoltaic performance, thus hindering their practical applications. In this work, Co 3 O 4 was investigated for application as a photo-absorber in all-oxide solar cells, and its band gap was optimized by introducing Li dopant into the spinel structure. Li x Co 3−x O 4 nanoparticles, prepared via the hydrothermal method, were homogenously coated onto TiO 2 mesoporous films, which were then used to fabricate planar heterojunction TiO 2 /Li x Co 3−x O 4 solar cells (SCs). The effects of Li-doping on the heterojunction solar cell performance were further investigated. The findings revealed that the incorporation of Li ions into Co 3 O 4 led to a significant enhancement in short-circuit current density (J sc ). Remarkably, a high open-circuit voltage (V oc ) of 0.70 V was also achieved. Besides, reasons for the enhanced cell performance are the narrower band gap, reduced photogenerated carrier recombination and the more favorable energy band structure as compared with SCs assembled from pure Co 3 O 4 .

Nanocomposites (integrating the nano and composite technologies) for advanced fuel cells (NANOCOFC) demonstrate the great potential to reduce the operational temperature of solid oxide fuel cell (SOFC) significantly in the low temperature (LT) range 300-600ºC. NANOCOFC has offered the development of multi-functional materials composed of semiconductor and ionic materials to meet the requirements of low temperature solid oxide fuel cell (LTSOFC) and green energy conversion devices with their unique mechanisms.This work reviews the recent developments relevant to the devices and the patents in LTSOFCs from nanotechnology perspectives that reports advances including fabrication methods, material compositions, characterization techniques and cell performances.Finally, the future scope of LTSOFC with nanotechnology and the practical applications are also discussed.

Semiconducting-ionic conductors have been recently described as excellent electrolyte membranes for low-temperature operation solid oxide fuel cells (LT-SOFCs). In the present work, two new functional materials based on zinc oxide (ZnO)—a legacy material in semiconductors but exceptionally novel to solid state ionics—are developed as membranes in SOFCs for the first time. The proposed ZnO and ZnO-LCP (La/Pr doped CeO2) electrolytes are respectively sandwiched between two Ni0.8Co0.15Al0.05Li-oxide (NCAL) electrodes to construct fuel cell devices. The assembled ZnO fuel cell demonstrates encouraging power outputs of 158–482 mW cm−2 and high open circuit voltages (OCVs) of 1–1.06 V at 450–550 °C, while the ZnO-LCP cell delivers significantly enhanced performance with maximum power density of 864 mW cm−2 and OCV of 1.07 V at 550 °C. The conductive properties of the materials are investigated. As a consequence, the ZnO electrolyte and ZnO-LCP composite exhibit extraordinary ionic conductivities of 0.09 and 0.156 S cm−1 at 550 °C, respectively, and the proton conductive behavior of ZnO is verified. Furthermore, performance enhancement of the ZnO-LCP cell is studied by electrochemical impedance spectroscopy (EIS), which is found to be as a result of the significantly reduced grain boundary and electrode polarization resistances. These findings indicate that ZnO is a highly promising alternative semiconducting-ionic membrane to replace the electrolyte materials for advanced LT-SOFCs, which in turn provides a new strategic pathway for the future development of electrolytes.