Energy Conversion Storage Devices Research Articles

Recent progress and future perspectives of flexible metal‐air batteries

AbstractWith the rapid development of wearable and intelligent flexible electronic devices (FEDs), the demand for flexible energy storage/conversion devices (ESCDs) has also increased. Rechargeable flexible metal‐air batteries (MABs) are expected to be one of the most ideal ESCDs due to their high theoretical energy density, cost advantage, and strong deformation adaptability. With the improvement of the device design, material assemblies, and manufacturing technology, the research on the electrochemical performance of flexible MABs has made significant progress. However, achieving the high mechanical flexibility, high safety, and wearable comfortability required by FEDs while maintaining the high performance of flexible MABs are still a daunting challenge. In this review, flexible Zn‐air and Li‐air batteries are mainly exemplified to describe the most recent progress and challenges of flexible MABs. We start with an overview of the structure and configuration of the flexible MABs and discuss their impact on battery performance and function. Then it focuses on the research progress of flexible metal anodes, gel polymer electrolytes, and air cathodes. Finally, the main challenges and future research perspectives involving flexible MABs for FEDs are proposed.

Energetic and exergetic analysis of an innovative plant for the production of electricity and substitute natural gas

The increasing penetration of intermittent and aleatory RES such as photovoltaics and wind power poses new challenges in terms of grid stabilization. Surplus electric energy needs to be stored, if not curtailed. From this point of view, chemical storage can pave the way for a long-term shift between demand and production, together with sector interconnection. Hydrogen as an energy vector has been deeply studied but it has difficulties in asserting itself due to its low energy density at environmental conditions and lack of infrastructure. In previous papers, an innovative plant for the conversion of biomass and fluctuating electric power into substitute natural gas and stable electricity has been designed and analysed in terms of its overall performances. The adoption of an electrolyser for hydrogen production allows to use part of the oxygen for the biomass gasification and the syngas oxy-combustion. The resulting combustion products have high carbon dioxide concentration, which avoids energy consuming separation equipment. This paper analyses in detail the plant performances in terms of energetic and exergetic efficiencies, components by components. The plant is simulated with the commercial software AspenONE® V9. Losses allocation and optimum operating conditions are identified. The proposed heat recovery strategies allow consistent energy savings, making this plant competitive with other energy storage conversion devices in terms of energy efficiency.

Preparation of Ultrathin Chiffon-like Ni-Al LDHs/Graphene Composite: Interlayer Stacking of Two-Dimensional Charged Panels via Electrostatic Self-Assembly for Supercapacitor Electrodes

In this article, Ni-Al LDHs/graphene composite is successfully fabricated via exfoliation and restacking method. As fabricated composite exhibits ultrathin nature of exfoliated LDHs deposited onto surface of graphene, yielding special chiffon like structure. Such structure can effectively overcome the agglomeration of initial LDHs and graphene sheets. The results of electrochemical performance confirm that Ni-Al LDHs/graphene composite exhibit enhanced performance in comparison with LDHs, which is related to the special chiffon like structure and high conductivity of graphene nanosheets. High performance of as-fabricated material can be identified via various electrochemical tests. In addition, an assembled asymmetric supercapacitor based on Ni-Al LDHs/graphene and active carbon exhibits a maximum energy density of 46.4 Wh kg−1 as well as a maximum power density of 6080 W kg−1, which indicates the potential of composite applied in energy storage-conversion devices.

Facile one-step synthesis of nanocomposite based on carbon nanotubes and Nickel-Aluminum layered double hydroxides with high cycling stability for supercapacitors

Nickel-Aluminum Layered Double Hydroxide (NiAl-LDH) and nanocomposite of Carbon Nanotubes (CNTs) and NiAl-LDH (CNTs/NiAl-LDH) were prepared by using a facile one-step homogeneous precipitation approach. The morphology, structure and electrochemical properties of the as-prepared CNTs/NiAl-LDH nanocomposite were then systematically studied. According to the galvanostatic charge-discharge curves, the CNTs/NiAl-LDH nanocomposite exhibited a high specific capacitance of 694Fg−1 at the 1Ag−1. Furthermore, the specific capacitance of the CNTs/NiAl-LDH nanocomposite still retained 87% when the current density was increased from 1 to 10Ag−1. These results indicated that the CNTs/NiAl-LDH nanocomposite displayed a higher specific capacitance and rate capability than pure NiAl-LDH. And the participation of CNTs in the NiAl-LDH composite improved the electrochemical properties. Additionally, the capacitance of the CNTs/NiAl-LDH nanocomposite kept at least 92% after 3000cycles at 20Ag−1, suggesting that the nanocomposite exhibited excellent cycling durability. This strategy provided a facile and effective approach for the synthesis of nanocomposite based on CNTs and NiAl-LDH with enhanced supercapacitor behaviors, which can be potentially applied in energy storage conversion devices.