High-performance Energy Conversion Research Articles

“Island-bridge”-structured nanofluidic membranes for high-performance aqueous energy conversion and storage

“Island-bridge”-structured nanofluidic membranes for high-performance aqueous energy conversion and storage

Polyoxometalate-based plasmonic electron sponge membrane for nanofluidic osmotic energy conversion.

Nanofluidic membranes have demonstrated great potential in harvesting osmotic energy. However, the output power densities are usually hampered by insufficient membrane permselectivity. Herein, we design a polyoxometalates (POMs)-based nanofluidic plasmonic electron sponge membrane (PESM) for highly efficient osmotic energy conversion. Under light irradiation, hot electrons are generated on Au NPs surface and then transferred and stored in POMs electron sponges, while hot holes are consumed by water. The stored hot electrons in POMs increase the charge density and hydrophilicity of PESM, resulting in significantly improved permselectivity for high-performance osmotic energy conversion. In addition, the unique ionic current rectification (ICR) property of the prepared nanofluidic PESM inhibits ion concentration polarization effectively, which could further improve its permselectivity. Under light with 500-fold NaCl gradient, the maximum output power density of the prepared PESM reaches 70.4 W m-2, which is further enhanced even to 102.1 W m-2 by changing the ligand to P5W30. This work highlights the crucial roles of plasmonic electron sponge for tailoring the surface charge, modulating ion transport dynamics, and improving the performance of nanofluidic osmotic energy conversion.

Optimal Modeling of Ni/YSZ Triple Phase Boundary in Solid Oxide Cells Using First-Principles Calculations

Power generation with renewable energy using solid oxide cells (SOCs) has been widely researched. To solve the existing problems of SOCs, such as degradation and efficiency improvement, it is essential to understand reaction mechanisms on the surface/interface such as triple phase boundary (TPB) composed of catalysts, electrolytes, and gas phases. However, a reliable TPB model has not been uniquely defined to discuss the property. This study focused on the TPB model comprising Ni catalysts, yttria-stabilized zirconia (YSZ) electrolytes, and gas phases, and aimed to theoretically identify a reliable TPB model by using density functional theory calculations. The stable structure of YSZ surface models was first identified considering various oxygen vacancy positions, yttrium atom arrangements, yttria concentration, and YSZ surfaces. Thereafter, a reliable Ni/YSZ interface model was discussed by evaluating various Ni structure types, Ni interfaces in contact with the YSZ surface, and interface positions. As a result, we have proposed a more reliable YSZ surface structure than previous reports and reasonable Ni/YSZ interface models considering the computational cost to discuss the properties of TPB. These findings will contribute to the improved design of SOCs as high-performance energy conversion systems for sustainable energy storage.

Nanostructured Materials for Enhanced Performance of Solid Oxide Fuel Cells: A Comprehensive Review

Solid oxide fuel cells (SOFCs) have emerged as promising candidates for efficient and environmentally friendly energy conversion technologies. Their high energy conversion efficiency and fuel flexibility make them particularly attractive for various applications, ranging from stationary power generation to portable electronic devices. Recently, research has focused on utilizing nanostructured materials to enhance the performance of SOFCs. This comprehensive review summarizes the latest advancements in the design, fabrication, and characterization of nanostructured materials integrated in SOFC. The review begins by elucidating the fundamental principles underlying SOFC operation, emphasizing the critical role of electrode materials, electrolytes, and interfacial interactions in overall cell performance, and the importance of nanostructured materials in addressing key challenges. It provides an in-depth analysis of various types of nanostructures, highlighting their roles in improving the electrochemical performance, stability, and durability of SOFCs. Furthermore, this review delves into the fabrication techniques that enable precise control over nanostructure morphology, composition, and architecture. The influence of nanoscale effects on ionic and electronic transport within the electrolyte and electrodes is thoroughly explored, shedding light on the mechanisms behind enhanced performance. By providing a comprehensive overview of the current state of research on nanostructured materials for SOFCs, this review aims to guide researchers, engineers, and policymakers toward the development of high-performance, cost-effective, and sustainable energy conversion systems.

Designing Atomic Interface in Sb2 S3 /CdS Heterojunction for Efficient Solar Water Splitting.

In the emerging Sb2 S3 -based solar energy conversion devices, a CdS buffer layer prepared by chemical bath deposition is commonly used to improve the separation of photogenerated electron-hole pairs. However, the cation diffusion at the Sb2 S3 /CdS interface induces detrimental defects but is often overlooked. Designing a stable interface in the Sb2 S3 /CdS heterojunction is essential to achieve high solar energy conversion efficiency. As a proof of concept, this study reports that the modification of the Sb2 S3 /CdS heterojunction with an ultrathin Al2 O3 interlayer effectively suppresses the interfacial defects by preventing the diffusion of Cd2+ cations into the Sb2 S3 layer. As a result, a water-splitting photocathode based on Ag:Sb2 S3 /Al2 O3 /CdS heterojunction achieves a significantly improved half-cell solar-to-hydrogen efficiency of 2.78% in a neutral electrolyte, as compared to 1.66% for the control Ag:Sb2 S3 /CdS device. This work demonstrates the importance of designing atomic interfaces and may provide a guideline for the fabrication of high-performance stibnite-type semiconductor-based solar energy conversion devices.

Large-Scale, Vertically Aligned 2D Subnanochannel Arrays by a Smectic Liquid Crystal Network for High-Performance Osmotic Energy Conversion.

The osmotic energy, an abundant renewable energy source, can be directly converted to electricity by nanofluidic devices with ion-selective membranes. 2D nanochannels constructed by nanosheets possess abundant lateral interfacial ion-exchange sites and exhibit great superiority in nanofluidic devices. However, the most accessible orientation of the 2D nanochannels is parallel to the membrane surface, undoubtedly resulting in the conductivity loss. Herein, first vertically aligned 2D subnanochannel arrays self-assembled by a smectic liquid crystal (LC) network that exhibit high-performance osmotic energy conversion are demonstrated. The 2D subnanochannel arrays are fabricated by in situ photopolymerization of monomers in the LC phase. The as-prepared membrane exhibits excellent water-resistance and mechanical strength. The 2D subnanochannels with excellent cation selectivity and conductivity show high-performance osmotic energy conversion. The power density reaches up to about 22.5W m-2 with NaCl solution under a 50-fold concentration gradient, which is among with ultrahigh power density. This membrane design concept provides promising applications in osmotic energy conversion.

Ultrathin H-MXM as An "Ion Freeway" for High-Performance Osmotic Energy Conversion.

Nanofluidic membranes are currently being explored as potential candidates for osmotic energy harvesting. However, the development of high-performance nanofluidic membranes remains a challenge. In this study, the ultrathin MXene membrane (H-MXM) is prepared by ultrathin slicing and realize the ion horizontal transportation. The H-MXM membrane, with a thickness of only 3 µm and straight subnanometer channels, exhibits ultrafast ion transport capabilities resembling an "ion freeway". By mixing artificial seawater and river water, a power output of 93.6 Wm-2 is obtained. Just as cell membranes have an ultrathin thickness that allows for excellent penetration, this straight nanofluidic membrane also possesses an ultrathin structure. This unique feature helps to shorten the ion transport path, leading to an increased ion transport rate and improveS performance in osmotic energy conversion.

Nano-Confined Effect and Heterojunction Promoted Exciton Separation for Light-Boosted Osmotic Energy Conversion.

The osmotic energy conversion properties of biomimetic light-stimulated nanochannels have aroused great interest. However, the power output performance is limited by the low light-induced current and energy conversion efficiency. Here, nanochannel arrays with simultaneous modification of ZnO and di-tetrabutylammonium cis-bis(isothiocyanato)bis(2,20-bipyridyl-4,40-dicarboxylato) ruthenium (II) (N719) onto anodic aluminum oxide (AAO) to combine the nano-confined effect and heterojunction is designed, which demonstrate rectified ion transport behavior due to the asymmetric composition, structure and charge. High cation selectivity and ion flux contribute to the high power density of ≈7.33Wm-2 by mixing artificial seawater and river water. Under light irradiation, heterojunction promoted the production and separation of exciton, enhanced cation selectivity, and improved the utilization efficiency of osmotic energy, providing a remarkable power density of ≈18.49Wm-2 with an increase of 252% and total energy conversion efficiency of 30.43%. The work opens new insights into the biomimetic nanochannels for high-performance energy conversion.

Low-Dimensional Vanadium-Based High-Voltage Cathode Materials for Promising Rechargeable Alkali-Ion Batteries.

Owing to their rich structural chemistry and unique electrochemical properties, vanadium-based materials, especially the low-dimensional ones, are showing promising applications in energy storage and conversion. In this invited review, low-dimensional vanadium-based materials (including 0D, 1D, and 2D nanostructures of vanadium-containing oxides, polyanions, and mixed-polyanions) and their emerging applications in advanced alkali-metal-ion batteries (e.g., Li-ion, Na-ion, and K-ion batteries) are systematically summarized. Future development trends, challenges, solutions, and perspectives are discussed and proposed. Mechanisms and new insights are also given for the development of advanced vanadium-based materials in high-performance energy storage and conversion.

High performance hydrogen evolution energy conversion devices via p type polaron surface state modulation

The processing of solar to hydrogen energy conversion semiconductor devices strongly relies on the charge mobility and reactivity of hydrogen evolution reactions. Intrinsic defects induced polaron has been applied on the surface of Cu2O polyhedron nanoparticles to modulate the hydrogen cations reduction and hydrogen evolution reaction by high charge mobility and H atoms high selective of specific external terminated atoms. With the polaron surface state applied on truncated octahedron Cu2O nanoparticle photocathode, the water splitting efficiency achieved 2.12 % at 0.2 V working bias. The hydrogen generation rate is as high as 9.38 L/m2⋅h. Besides, under 1.23 V applied bias, at 1 atm pressure and room temperature, there are over 64 L hydrogen gases are generated in only one hour, and the hydrogen generation rate is as high as 65.39 L/m2⋅h. During this study, a defined p typed polaron surface state for raising charge mobility and hydrogen evolution in solar to hydrogen conversion system is illustrated, which provides the reliable application in related photon to electron conversion and high performance energy conversion devices.

Two-dimensional ternary pentagonal BCX (X = P, As, and Sb): promising photocatalyst semiconductors for water splitting with strong piezoelectricity.

Seeking high-performance energy conversion materials is one of the most important issues in designing 2D materials. In the framework of density functional theory, we propose a series of ternary monolayers, penta-BCX (X = P, As, and Sb), and systematically investigate their structural stability, mechanical, piezoelectric, and photocatalytic properties. All three materials are semiconductors with a bandgap ranging from 2.56 eV to 3.24 eV, so they could be promising catalysts for the photolysis of water. Penta-BCX exhibits significant piezoelectric properties attributed to their non-centrosymmetric structure and low in-plane Young's modulus, which are expected to efficiently drive photocatalytic water decomposition. Moreover, the bandgap, band edge position, and light absorption of penta-BCX can be modulated by tensile or compressive strain to enhance their photocatalytic performance in the visible light and ultraviolet regions.

Flake-like SnS anchored on the carbon layer for supercapacitor electrode with photo-responsive capacitance enhancement

Photo-responsive supercapacitors incorporate light-responsive materials on capacitive electrodes, making them capable of solar energy conversion and storage within single device. Herein, composite structures consisting of flake-like stannous sulfide (SnS) anchored on a carbon layer (CL) covered nickel foam (CL@SnS/NF) are synthesized as photo-responsive supercapacitor electrode for capacitance enhancement under visible light. SnS as a light-absorbing layer has a narrow bandgap that matches well with the wavelength of visible light, while CL serves as an electron transport channel for effective separation of photogenerated carriers. Due to the synergetic effect of two components above, the areal specific capacitance of the CL@SnS/NF electrode increases from 15.7 to 21.0 mF·cm−2 in light conditions under 0.1 mA·cm−2, which is 1.7 and 6.6 times larger than that of CL/NF and SnS/NF electrodes under the same conditions, respectively, indicating the remarkable light-induced capacitance enhancement performance. The CL@SnS/NF electrode also presents higher photocurrent and photovoltage than two single electrodes, implying its excellent photosensitivity. In addition, the assembled CL@SnS/NF-based symmetric supercapacitor exhibits great capacitance gain under illumination (185.8% at 50 µA·cm−2) and excellent capacitance maintenance (87.7% over 6000 cycles). This work supplies a novel strategy to the development of high-performance solar energy conversion and storage devices.

High Thermoelectric Performance in Phonon-Glass Electron-Crystal Like AgSbTe2.

Achieving glass-like ultra-low thermal conductivity in crystalline solids with high electrical conductivity, a crucial requirement for high-performance thermoelectrics , continues to be a formidable challenge. A careful balance between electrical and thermal transport is essential for optimizing the thermoelectric performance. Despite this inherent trade-off, the experimental realization of an ideal thermoelectric material with a phonon-glass electron-crystal (PGEC) nature has rarely been achieved. Here, PGEC-like AgSbTe2 is demonstrated by tuning the atomic disorder upon Yb doping, which results in an outstanding thermoelectric performance with figure of merit, zT ≈ 2.4 at 573 K. Yb-doping-induced enhanced atomic ordering decreases the overlap between the hole and phonon mean free paths and consequently leads to a PGEC-like transport behavior in AgSbTe2 . A twofold increase in electrical mobility is observed while keeping the position of the Fermi level (EF ) nearly unchanged and corroborates the enhanced crystalline nature of the AgSbTe2 lattice upon Yb doping for electrical transport. The cation-ordered domains, lead to the formation of nanoscale superstructures (≈2 to 4nm) that strongly scatter heat-carrying phonons, resulting in a temperature-independent glass-like thermal conductivity. The strategy paves the way for realizing high thermoelectric performance in various disordered crystals by making them amorphous to phonons while favoring crystal-like electrical transport.

RGO and CNTs synergistically modified mixed-phase nickel sulfide nanohybrids with abundant redox-active sites for high-performance hybrid supercapacitors

Hybrid supercapacitors (HSCs) integrating high energy density and power density have great prospects for applications in new high-performance energy storage and conversion devices. Herein, a novel reduced graphene oxide (RGO) and carbon nanotubes (CNTs) synergistically modified mixed-phase nickel sulfide (NiS/NiS2) nanohybrids (NSRCs) were successfully designed and synthesized by a facile one-step solvothermal method. Benefiting from the high conductivity and high specific surface area of carbon materials and the high specific capacity of nickel sulfide, as well as the stable nanostructures constructed by the synergistic effect of multiple components, the synthesized novel NSRCs nanohybrids exhibit impressive electrochemical performances, such as high specific capacity of 178.2 mAh g−1 (1604.1 F g−1) at 0.6 A g−1, excellent rate capability (57.3 % at 20 A g−1). Furthermore, the assembled hybrid supercapacitors (NSRC-24//AC HSC) with optimal NSRC-24 electrode and activated carbon (AC) electrode imparted a high energy density of 44.2 Wh kg−1 at a power density of 359.2 W kg−1 and excellent cycling stability (98.1 % capacity retention after 12,000 cycles at 5 A g−1). Thus, the synthesized novel NSRCs nanohybrids are highly promising candidates as advanced electrode materials for aqueous high-performance energy storage devices.

Hierarchical wood cells impose well-textured carbon nanotubes with cobalt single atoms: Bioinspired construction and application in zinc–air battery

The construction of oxygen reduction reaction (ORR) electrocatalysts with well-textured structure and desirable activity remains great challenge for the complicated procedures and poor interface. Herein, inspired by sea anemones, the highly ordered Co–based carbon nanotubes electrocatalysts were elaborately assembled on wood fibers via stoichiometry. The porous cell-wall and abundant oxygen groups in lignocellulosic scaffold impose such preferable structure, in which the Co–based carbon nanotubes with Co single atoms and Co nanoparticles were tuned to possess higher catalytic activity and capture more oxygen species. As expected, the as-prepared electrocatalyst displays outstanding ORR performance with a half-wave potential of 0.9 V. The assembled Zn–air battery using this cathode catalyst shows a high-power density of 196 mW cm−2, superior to the commercial Pt/C catalysts. This work could inspire developing other biomimetic architectures for high-performance energy storage and conversion systems.

Carbon coated hetero sulfides nanoboxes with efficient pseudocapacitive behavior for sodium storage

Engineering heterojunction with the interfacial synergism is an effective anode design strategy to innovate the surface pseudocapacitive reaction and facilitate the charge transfer dynamics, thus resulting in improved properties for sodium-ion batteries. Herein, the heterogeneous structure of Sb2S3-CoS2 nanoboxes coated with nitrogen-doped carbon shell (Sb2S3-CoS2@NC) is fabricated through the replacement of Co2+ with Sb3+, and the subsequent sulfurization reaction. The advantages of exquisite hollow structure and carbon coating not only effectively buffer the vast volumetric variation to prevent the collapse of electrode but also accelerate the charge transfer to optimize rate property. Moreover, the interfacial synergism between Sb2S3-CoS2 heterojunction improves surface pseudocapacitive Na+ uptake and boosts the Na+ transport. Consequently, the developed Sb2S3-CoS2@NC nanoboxes exhibit advanced anode performances of high specific capacity, stable cyclic durability, and good rate capability. This approach can be utilized to develop other hollow structured heterogeneous materials for high performance energy storage and conversion application.

Reconfigurable hybrid micro-grid with standardized power module for high performance energy conversion

This paper proposes a reconfigurable power module system for hybrid micro-grid to reduce the designing cost with standardized software and hardware components. The developed system is composed of three layers including application function layer, interconnection layer and physical layer with the capability to be interfaced with different types of energy resources for the hybrid micro-grid. By implementing the multi-layer power module system, the energy conversion designing procedures for different types of resources can be generalized and automated with less cost on the specified application scenarios. The control functions for different energy resources can be extracted from the application function layer. The desired number of standardized power modules can be integrated from the physical layer to form different power converter topologies. The coordination of the power converter, micro-controller, sampling, high level control is managed by the interconnection layer to construct the complete energy conversion system. The major advantageous results cover three aspects. Firstly, the proposed reconfigurable system generalizes the energy conversion of the hybrid micro-grid with different AC and DC resources. Secondly, the designing procedures of the hybrid micro-grid energy conversion system are simplified with less cost for various interfaced applications. Thirdly, the energy conversion performance and reliability of the micro-grid is improved with standardized power modules and self-restoration capability. The experimental test verified the proposed system.

Electric Field-Assisted Self-Assembly of Diphenylalanine Peptides for High-Performance Energy Conversion

Electric Field-Assisted Self-Assembly of Diphenylalanine Peptides for High-Performance Energy Conversion

Graphene Nanocomposites as Innovative Materials for Energy Storage and Conversion-Design and Headways.

This review mainly addresses applications of polymer/graphene nanocomposites in certain significant energy storage and conversion devices such as supercapacitors, Li-ion batteries, and fuel cells. Graphene has achieved an indispensable position among carbon nanomaterials owing to its inimitable structure and features. Graphene and its nanocomposites have been recognized for providing a high surface area, electron conductivity, capacitance, energy density, charge-discharge, cyclic stability, power conversion efficiency, and other advanced features in efficient energy devices. Furthermore, graphene-containing nanocomposites have superior microstructure, mechanical robustness, and heat constancy characteristics. Thus, this state-of-the-art article offers comprehensive coverage on designing, processing, and applying graphene-based nanoarchitectures in high-performance energy storage and conversion devices. Despite the essential features of graphene-derived nanocomposites, several challenges need to be overcome to attain advanced device performance.

Scalable fabrication of regenerated cellulose nanohybrid membranes integrating opposite charges and aligned nanochannels for continuous osmotic energy harvesting

Nanomaterials are widely used in constructing reverse electrodialysis (RED) systems with charged nanochannels for osmotic energy harvesting. However, preparing low-cost, large-scale, and high-performance RED systems with significantly improved ion selectivity, ion flux, and output power density is still a challenge. Herein, we develop a facile solution-casting method to fabricate oriented regenerated cellulose (RC)/carbon nanotubes (CNTs) nanohybrid membranes. After integrating chemical modification (i.e., TEMPO oxidation and quaternization) and structural densification, both negatively charged N-RC/N-CNTs and positively charged P-RC/P-CNTs membranes demonstrated significantly enhanced ionic conductivity in a low-concentration solution (4.02 ×10−4 and 3.59 ×10−4 S cm−1, respectively). Particularly, the P–N unit not only yields an output power density of 5.28 W m−2 in a 50-fold concentration gradient, which exceeds the commercial standard (5 W m−2), but also achieves long-term stability over 50 days. As a proof of concept, we created a RED system with 20 P–N units connected in series which successfully powered an electronic calculator with an output voltage of 2.06 V under artificial seawater and river water conditions. This work improves the development of natural renewable materials for high-performance osmotic energy conversion.