Materials For Energy Conversion Research Articles

Wood derived carbon embedded with shell-core CoP@CoFe for efficient oxygen evolution

Development of hybrid materials with specific architecture, interface, and multicomponent interactions demonstrates effective paradigm for pursuing high-performance energy conversion materials. Herein, using renewable and inexpensive wood-derived carbon as host, the shell-core CoP@CoFe particles are embedded on walls of carbonized wood channels (termed as CoP@CoFe/CW) to fabricate composite catalyst for electrocatalysis oxygen evolution reaction (OER). With benefits of the well distribution of CoP@CoFe particles, high conductivity of CW with channels, and good integration between them, highly exposed catalysis surface as well as rapid charge/mass transfer are achieved. The interface effect of shell-core hybrid activates the intrinsic OER efficiency of CoP@CoFe. Thus, the designed CoP@CoFe/CW yields excellent OER performance with ultralow overpotential of 120 mV (10 mA cm−2). This strategy of catalyst design based on eco-friendliness and renewable CW host may offer promising reference to explore composite materials with high conductivity and fast mass transfer for water electrolysis and other energy storage/conversion systems.

Van der Waals gap engineering in 2D materials for energy storage and conversion

Van der Waals gap engineering in 2D materials for energy storage and conversion

Nanoporous Carbon Materials Derived from Biomass Precursors: Sustainable Materials for Energy Conversion and Storage

Nanoporous Carbon Materials Derived from Biomass Precursors: Sustainable Materials for Energy Conversion and Storage

Synthesis of Cs3Cu2I5 Nanocrystals in a Continuous Flow System.

Achieving the goal of generating all of the world's energy via renewable sources and significantly reducing the energy usage will require the development of novel, abundant, nontoxic energy conversion materials. Here, a cost-efficient and scalable continuous flow synthesis of Cs3Cu2I5 nanocrystals is developed as a basis for the rapid advancement of novel nanomaterials. Ideal precursor solutions are obtained through a novel batch synthesis, whose product served as a benchmark for the subsequent flow synthesis. Realizing this setup enabled a reproducible fabrication of Cs3Cu2I5 nanocrystals. The effect of volumetric flow rate and temperature on the final product's morphology and optical properties are determined, obtaining 21% quantum yield with the optimal configuration. Consequently, the size and morphology of the nanocrystals can be tuned with far more precision and in a much broader range than previously achievable. The flow setup is readily applicable to other relevant nanomaterials. It should enable a rapid determination of a material's potential and subsequently optimize its desired properties for renewable energy generation or efficient optoelectronics.

Precursor engineering for soft selective synthesis of phase pure metal-rich digenite (Cu9S5) and djurleite (Cu31S16) nanocrystals and investigation of their photo-switching characteristics.

Copper sulfide nanostructures have evolved as one of the most technologically important materials for energy conversion and storage owing to their economic and non-toxic nature and superior performances. This paper presents a direct, scalable synthetic route aided by a single source molecular precursor (SSP) approach to access copper sulfide nanomaterials. Two SSPs, CuX(dmpymSH)(PPh3)2 (where X = Cl or I), were synthesized in quantitative yields and thermolyzed under appropriate conditions to afford the nanostructures. The analysis of the nanostructures through pXRD, EDS and XPS suggested that phase pure digenite (Cu9S5) and djurleite (Cu31S16) nanostructures were isolated from -Cl and -I substituted SSPs, respectively. The morphologies of the as-synthesized nanomaterials were investigated using electron microscopy techniques (SEM and TEM). DRS studies on pristine materials revealed blue shifted optical band gaps, which were found to be optimum for photoelectrochemical application. A prototype photoelectrochemical cell fabricated using the pristine nanostructures exhibited a stable photo-switching property, which presents these materials as suitable economic and environmentally friendly photon absorber materials.

Carbonized wood fiber-supported S, N-codoped carbon layer-coated multinary metal sulfide nanoarchitecture for efficient oxygen evolution reaction at ampere-level current density

Multinary metal sulfides (MMSs) are highly suitable candidates for the application of electrocatalysis as they offer numerous parameters for optimizing the electronic structure and catalytic sites. Herein, a stable nanoarchitecture consisting of MMSs ((NiCoCrMnFe)Sx) nanoparticles embedded in S, N-codoped carbon (SNC) layers derived from metal organic framework (MOF) and supported on carbonized wood fibers (CWF) was fabricated by directly carbonization. Benefiting from this carbon-coated configuration, along with the synergistic effects within multinary metal systems, (NiCoCrMnFe)Sx@SNC/CWF delivers an exceptionally low overpotential of 260 mV at a high current density of 1000 mA cm−2, a small Tafel slope of 48.5 mV dec−1, and robust electrocatalytic stability. Furthermore, the (NiCoCrMnFe)Sx@SNC/ CWF used as the cathode of rechargeable Zn-air batteries demonstrates higher power density and remarkable durability, surpassing that of commercial RuO2. Thus, we showcase the feasibility and advantages of employing highly efficient and durable MMSs materials for low-cost and sustainable energy conversion.

Energy Storage Application of CaO/Graphite Nanocomposite Powder Obtained from Waste Eggshells and Used Lithium-Ion Batteries as a Sustainable Development Approach.

The reuse of waste materials has recently become appealing due to pollution and cost reduction factors. Using waste materials can reduce environmental pollution and product costs, thus promoting sustainability. Approximately 95% of calcium carbonate-containing waste eggshells end up in landfills, unused. These eggshells, a form of bio-waste, can be repurposed as catalytic electrode material for various applications, including supercapacitors, after being converted into CaO. Similarly, used waste battery electrode materials pose environmental hazards if not properly recycled. Various types of batteries, particularly lithium-ion batteries, are extensively used worldwide. The recycling of used lithium-ion batteries has become less important considering its low economic benefits. This necessitates finding alternative methods to recover and reuse the graphite rods of spent batteries. Therefore, this study reports the conversion of waste eggshell into calcium oxide by high-temperature calcination and extraction of nanographite from spent batteries for application in energy storage fields. Both CaO and CaO/graphite were characterized for their structural, morphological, and chemical compositions using XRD, SEM, TEM, and XPS techniques. The prepared CaO/graphite nanocomposite material was evaluated for its efficiency in electrochemical supercapacitor applications. CaO and its composite with graphite powder obtained from used lithium-ion batteries demonstrated improved performance compared to CaO alone for energy storage applications. Using these waste materials for electrochemical energy storage and conversion devices results in cheaper, greener, and sustainable processes. This approach not only aids in energy storage but also promotes sustainability through waste management by reducing landfills.

Optimized Electrodeposition of Ni2O3 on Carbon Paper for Enhanced Electrocatalytic Oxidation of Ethanol.

The urgent need for sustainable and efficient energy conversion technologies has propelled research into novel electrocatalysts for fuel cell applications. This study investigates a carbon paper (CP)-supported Ni2O3 catalyst for the electrocatalytic oxidation of ethanol. We utilized electrodeposition to uniformly deposit/dop Ni2O3 onto the CP, creating an effective electrocatalyst. Our approach allows the tailoring of the doping degree by adjusting the electrodeposition potential. The optimal doping degree, achieved at a medium deposition potential, results in an electrode with high intrinsic activity and a substantial electrochemically active surface area (ECSA), thereby enhancing its electrocatalytic activity. This catalyst efficiently facilitates the oxidation of ethanol to formic acid while maintaining good stability. The enhanced performance is attributed to the effective interface and interaction between Ni2O3 and CP. This work not only provides insights into the design of efficient Ni-based catalysts for ethanol oxidation but also paves the way for developing advanced materials for renewable energy conversion.

The Ferroelectric Effects of Rhombohedral and Tetragonal BiFeO3 in Photoelectrochemical Water Splitting.

The phase of BiFeO3 (BFO) as well as its domain configuration can be tuned by strain engineering. Phase change may greatly influence the properties of the polarization field and hence charge separation. However, the photoelectrochemical properties of different BFO phases have rarely been addressed. Here, the photoelectrochemical study of tetragonal (T-) and rhombohedral (R-) phase BFO films was conducted under visible light illumination. The photocurrent density of R-BFO is 5 times that of T-BFO. A ferroelectric domain study shows that T-BFO features single domain structure in contrast to the polydomain structure of R-BFO. Higher charge separation efficiency is achieved in R-BFO, dominated by the domain walls as conducting pathways for efficient charge separation and transfer. This work provides a fundamental understanding of the photoelectrochemical properties of T- and R-BFO, offering valuable insights for the development of BFO-based materials for solar energy conversion.

A Visible Light-Responsive TiO2 Photocathode Achieved by a Rh Dopant.

Developing an efficient and stable photocathode material for photoelectrochemical solar water splitting remains challenging. Herein, we demonstrate the potential of rutile TiO2 as a photocathode by Rh doping with visible light absorption up to 640 nm and an onset potential of 0.9 V versus the reversible hydrogen electrode. The dopant transforms the rutile host from an n-type semiconductor to a p-type one, as confirmed by the Mott-Schottky curve and kelvin probe force microscopy. Physical and photoelectrochemical analyses further suggest that the doping mechanism is dependent on concentration. Lower levels of dopants generate localized Rh3+, while higher levels favor Rh4+ that interacts more strongly with the O 2p orbitals. The latter is found not only to extend the visible light absorption range but also to facilitate charge transport. This work elucidates the role of the Rh dopant in adjusting the photoelectrochemical behavior of TiO2, and it provides a promising photocathode material for solar energy conversion.

Heterostructure Ni3P/CoP2/NiCo2O4/CC nanowire material as a trifunctional electrode for high-performance supercapacitors and electrocatalysis

The design and preparation of efficient and cost-effective multifunctional active materials for energy storage and conversion are essential component in achieving the current clean energy development. Herein, we have successfully synthesized heterostructure Ni3P/CoP2/NiCo2O4/CC nanowires with vertical array structure on carbon cloth by a simple strategy of solvothermal-annealing and phosphate treatment. The abundant heterogeneous interfaces and synergistic effect between the transition metal oxides/phosphides endow the material with excellent multifunctional properties. As a supercapacitor electrode, the Ni3P/CoP2/NiCo2O4/CC electrode possesses an exceptional specific capacitance of 2349 F g−1 at 1 A g−1. At a power density of 900 W kg−1, the built asymmetric supercapacitor achieves a high energy density of 37.5 Wh kg−1. Furthermore, an initial capacitance retention rate of 85 % was still maintained after 25,000 cycles. When used as electrocatalyst, the required oxygen evolution reaction and hydrogen evolution reaction overpotentials for a current density of 10 mA cm−2 are only 267 mV and 98 mV, respectively. Meanwhile, it presents superior overall water splitting activity (1.64 V@10 mA cm−2) and catalytic stability. This study affords additional perspectives for the reasonable design of non-noble metal based multifunctional materials to meet the diversified energy development.

II-Scheme Heterojunction Frameworks Based on Covalent Organic Frameworks and HKUST-1 for Boosting Photocatalytic Hydrogen Evolution.

Covalent organic frameworks (COFs) are one type of promising polymer semiconductors in solar-driven hydrogen production, but majority of COFs-based photocatalytic systems show low photocatalytic efficiency owing to lack of metal active sites. Herein, we reported II-Scheme heterojunction frameworks based on COF (TpPa-1) and metal-organic framework (HKUST-1) for highly efficient hydrogen production. The coordination bonding directed self-assembly of HKUST-1 on the surface of TpPa-1 endows the heterojunction frameworks (HKUST-1/TpPa-1) with strong interface interaction, optimized electronic structures and abundant redox active sites, thus remarkably boosting photocatalytic hydrogen evolution. The hydrogen evolution rate for optimal HKUST-1/TpPa-1 is as high as 10.50 mmol g-1 h-1, which is significantly enhanced when compared with that of their physical mixture (4.13 mmol g-1 h-1), TpPa-1 (0.013 mmol g-1 h-1) and Pt-based counterpart (6.70mmol g-1 h-1). This work offers a facile approach to the construction of noble-metal-free II-Scheme heterojunctions based on framework materials for efficient solar energy conversion.

Laser‐Induced Graphene Toward Flexible Energy Harvesting and Storage Electronics

AbstractEnergy harvesting and storage devices play an increasingly important role in the field of flexible electronics. Laser‐induced graphene (LIG) with hierarchical porosity, large specific surface area, high electrical conductivity, and mechanical flexibility is an ideal candidate for fabricating flexible energy devices which supply power for other electronic components. Through a simple laser irradiation process with designable routes, abundant precursors (or substrates) rapidly transform into patterned LIG without any other treatments. The structure and physicochemical properties of LIG can be regulated by controlling the processing strategies and parameters, enabling the optimization of device performance. The laser scribing method, as a non‐contact and in situ technique, proves to be efficient in integrating different LIG‐based devices, resulting in all‐in‐one flexible power platforms. Here, a systematic summary of recent advancements in LIG‐based flexible energy electronics is presented. The controllable synthesis of LIG, functional LIG, and 3D architectures are described by elucidating corresponding mechanisms and processing strategies. An overall review of flexible energy conversion and storage devices based on LIG is presented. Eventually, the challenges and opportunities of LIG‐based materials in flexible energy conversion and storage are briefly discussed.

Anomalous Correlation between Thermal Conductivity and Elastic Modulus in Two-Dimensional Hybrid Metal Halide Perovskites.

Device-level implementation of soft materials for energy conversion and thermal management demands a comprehensive understanding of their thermal conductivity and elastic modulus to mitigate thermo-mechanical challenges and ensure long-term stability. Thermal conductivity and elastic modulus are usually positively correlated in soft materials, such as amorphous macromolecules, which poses a challenge to discover materials that are either soft and thermally conductive or hard and thermally insulative. Here, we show anomalous correlations of thermal conductivity and elastic modulus in two-dimensional (2D) hybrid organic-inorganic perovskites (HOIP) by engineering the molecular interactions between organic cations. By replacing conventional alkyl-alkyl and aryl-aryl type organic interactions with mixed alkyl-aryl interactions, we observe an enhancement in elastic modulus with a reduction in thermal conductivity. This anomalous dependence provides a route to engineer thermal conductivity and elastic modulus independently and a guideline to search for better thermal management materials. Further, introducing chirality into the organic cation induces a molecular packing that leads to the same thermal conductivity and elastic modulus regardless of the composition across all half-chiral 2D HOIPs. This finding provides substantial leeway for further investigations in chiral 2D HOIPs to tune optoelectronic properties without compromising thermal and mechanical stability.

CuO nanoflowers: Multifaceted implications of various precipitating agents on rectification behaviour

In order to achieve the best possible use of traditional energy resources for the preservation of the environment, semiconductor-based optoelectronic devices are one of the most intriguing methods for converting light energy into electrical energy. CuO has been extensively explored as a material for energy conversion and the development of photo-detectors due to its notable characteristics among other metals, especially its non-toxicity, abundance, high efficiency, electrochemical stability and low cost/promising photodiode. However, some drawbacks limit its practical application in white light and photo-detector, including the rapid recombination rate of photo-generated electron-hole pairs and destitute response to visible light. As a result, several strategies have been developed from an optoelectronics perspective to eradicate these deficiencies and make an effort to enhance CuO photodiode activities. In this research work, the electrical characteristics and rectification behaviour of CuO with various precipitating agents have been examined. The CuO nanoparticles can be synthesized by co-precipitation technique prepared with different precipitants. Through this research, several parameters, such as the structural, functional, morphological, optical and electrical characteristics, were investigated by changing the precipitants. The functional group formation of pure CuO phase was confirmed by FT-IR studies. UV–Vis absorption measurements indicate that the band gap of the CuO nanoparticles was ranging from 2.40 to 2.85 eV. As a diode, CuO/p-Si exhibits a non-ideal behaviour and under light conditions with Na2CO3 precipitant, the better ideality factor is about 2.35. The barrier height is determined by the thermionic emission theory to be 0.77 and 0.79 eV in the dark and light conditions respectively.

A new FeS2/N-C nanoparticle from NH2-MIL-101 for high performance lithium ion batteries

Among multitudinous lithium storage electrode materials, transition metal sulfides have attracted widespread attention because of high theoretical capacity and wide availability. However, these anodes still suffer poor capacity retention and limited cycle life. Metal organic frameworks (MOFs) are important precursors for fabricating functional materials for energy conversion and storage. A study of their derivatization process is of great significance for the design of materials with specific functional properties. In this paper, a new FeS2/N-C nanoparticle is synthesized by calcination strategy from NH2-MIL-101 prepared by solvothermal method. Due to the coordination effect of nitrogen-doped carbon and special particle morphology, the synthesized FeS2/N-C nanoparticles have superior cycling stability and high reversible capacity. This work provides a better understanding of the carbonization process of MOFs and reveals the effect of N-doped and MOF synthesis time on transition metal sulfides.

Vanadium nitride induced method to construct cobalt sulfides homologous heterojunction toward ultrafast and high-capacity sodium-ion storage

In recent years, heterojunction has attracted widespread attention as an anode for sodium-ion batteries since they can effectively optimize the materials’ rate performance and cycling stability. However, the advantage is choked by multi-element composition and stepwise synthesis process. Herein, cobalt sulfide (Co9S8/CoS) homologous heterojunction deposited at vanadium nitride/carbon nanofibers is synthesized as an excellent anode for high-performance sodium-ion batteries in one step by employing the “3d-orbital electron complementary effect” combined with high-temperature heat-treatment technology. The Co9S8/CoS homologous heterojunction successfully overcomes the inherent drawback of Co9S8 and possesses an ultrafast charging/discharging process, outstanding reversible specific capacity, and remarkable rate capability. A systematic study reveals that vanadium nitride is a key trigger for forming Co9S8/CoS heterojunction. When used as anode materials for sodium-ion batteries, it reaches a high specific capacity of 353.0 mAh/g at a current density of 10 A/g (615.8 mAh/g at a current density of 0.05 A/g) due to the presence of heterointerface. Theoretical calculations show that the construction of the heterostructure enhances the sodium-ion storage capacity and storage kinetics compared with pristine Co9S8. This discovery opens an interesting strategy for constructing homogeneous heterojunctions and broadens the horizons for designing energy storage and conversion materials.

Organic Electrode Materials for Energy Storage and Conversion: Mechanism, Characteristics, and Applications.

ConspectusLithium ion batteries (LIBs) with inorganic intercalation compounds as electrode active materials have become an indispensable part of human life. However, the rapid increase in their annual production raises concerns about limited mineral reserves and related environmental issues. Therefore, organic electrode materials (OEMs) for rechargeable batteries have once again come into the focus of researchers because of their design flexibility, sustainability, and environmental compatibility. Compared with conventional inorganic cathode materials for Li ion batteries, OEMs possess some unique characteristics including flexible molecular structure, weak intermolecular interaction, being highly soluble in electrolytes, and moderate electrochemical potentials. These unique characteristics make OEMs suitable for applications in multivalent ion batteries, low-temperature batteries, redox flow batteries, and decoupled water electrolysis. Specifically, the flexible molecular structure and weak intermolecular interaction of OEMs make multivalent ions easily accessible to the redox sites of OEMs and facilitate the desolvation process on the redox site, thus improving the low-temperature performance, while the highly soluble nature enables OEMs as redox couples for aqueous redox flow batteries. Finally, the moderate electrochemical potential and reversible proton storage and release of OEMs make them suitable as redox mediators for water electrolysis. Over the past ten years, although various new OEMs have been developed for Li-organic batteries, Na-organic batteries, Zn-organic batteries, and other battery systems, batteries with OEMs still face many challenges, such as poor cycle stability, inferior energy density, and limited rate capability. Therefore, previous reviews of OEMs mainly focused on organic molecular design for organic batteries or strategies to improve the electrochemical performance of OEMs. A comprehensive review to explore the characteristics of OEMs and establish the correlation between these characteristics and their specific application in energy storage and conversion is still lacking.In this Account, we initially provide an overview of the sustainability and environmental friendliness of OEMs for energy storage and conversion. Subsequently, we summarize the charge storage mechanisms of the different types of OEMs. Thereafter, we explore the characteristics of OEMs in comparison with conventional inorganic intercalation compounds including their structural flexibility, high solubility in the electrolyte, and appropriate electrochemical potential in order to establish the correlations between their characteristics and potential applications. Unlike previous reviews that mainly introduce the electrochemical performance progress of different organic batteries, this Account specifically focuses on some exceptional applications of OEMs corresponding to the characteristics of organic electrode materials in energy storage and conversion, as previously published by our groups. These applications include monovalent ion batteries, multivalent ion batteries, low-temperature batteries, redox flow batteries with soluble OEMs, and decoupled water electrolysis employing organic electrodes as redox mediators. We hope that this Account will make an invaluable contribution to the development of organic electrode materials for next-generation batteries and help to unlock a world of potential energy storage applications.

Electrochemistry of 2D-materials for the remediation of environmental pollutants and alternative energy storage/conversion materials and devices, a comprehensive review

This review article explores into the complicated relationship between electrochemistry and 2D materials, exploring their mutual influences and the consequential advancements in energy conversion, storage, and environmental applications. Electrochemical reactions, manifested through oxidations and reductions at submerged electrodes, form the linchpin connecting the electrochemistry of 2D materials with their practical utility. Various electrochemical cell topologies are investigated for their role in enhancing material flexibility, operational states, energy conversion efficiency, and device design adaptability. The comprehensive discussion extends to diverse applications, emphasizing the pivotal roles of 2D materials in environmental remediation, alternate energy storage and conversion, and chemical reactivity. Noteworthy applications include pollutant detection, adsorption and absorption of pollutants, elimination of both organic and inorganic pollutants, and photocatalytic degradation. The review also addresses materials synthesis via electrochemical processes, detailing functionalization, handling, and deposition techniques. Particular focus is directed towards local electrochemical techniques enabling the analysis and local alteration of 2D materials. Moreover, this paper concludes the article published in the recent years with this topic and most significant trends observed in 2022 and 2023 with electrochemistry of materials for the remediation of environmental pollutants. While the trends of article publishing increased from 2020 to 2023 with topic alternative energy storage/conversion materials. Finally, offering a comprehensive overview of the synergistic relationship between electrochemistry and 2D materials and their transformative potential in sustainable technologies. Broader contextThe decreasing availability of energy resources and the contamination of the environment are two significant worldwide concerns that need immediate attention. The focus on 2D materials and associated technologies is important for the efficient conversion of solar energy into chemical energy. These materials have diverse applications in fields such as energy (e.g., water splitting), synthesis (e.g., production of valuable chemicals and N2 reduction), and the environment (e.g., CO2 reduction and environmental remediation). Furthermore, Electrochemical energy storage and conversion (EESC) technologies are widely acknowledged as the most viable solutions to address the escalating energy crisis and environmental degradation because to their exceptional energy efficiency and little environmental footprint. Currently, there have been several reports discussing the use of 2D-materials in energy applications and wastewater treatment. However, there is a lack of comprehensive reviews that summarize the electrochemistry of 2D-materials, their preparation strategies, modification techniques, and related properties. Furthermore, there is a need for detailed analysis of the progress in applying 2D-materials for environmental pollution remediation, electrocatalytic performance, energy storage, and conversion technologies and devices. In this paper, we systematically and comprehensively review the electrochemistry of 2D-materials and innovatively analyze the design principles and difficulties of 2D-materials. We discussed comprehensively the remediation of environmental pollutants through 2D-materials in water treatment fields such as photocatylsts, adsorption/absorption and dyes removal as an entry point and provide an in-depth knowledge and outlook on the current status and development potential of specific applications of energy storage and conversion materials and devices.

Understanding the effect of multiple configurations in polymeric carbon nitride for efficient solar-driven hydrogen peroxide photosynthesis

A oxygen and potassium co-doped polymeric carbon nitride (O/K-PCNs) was simply constructed by an acid gas cutting strategy for photocatalytic H2O2 generation. The effect of each accompanied configurations on photosynthesis of H2O2 was systematically analyzed. The C–O–C structure formed by O doping is capable of decreasing K ions incorporated energy barrier, thus remarkably improving the content of crucial K active sites. Dual heteroatom sites synergistically enhance O2 adsorption and surface ORR by a bridge K–O–O–C model. Moreover, the accompanied cyano defect and poly(heptazine imide) is responsible for improving in-plane and interlayer carriers separation, respectively. The optimal O/K-PCNs exhibits 60-fold higher photocatalytic H2O2 production rate than pure PCN. A positive correlation between the H2O2 production rate and the K heteratoms content was established. This work clarifies role of multiple configurations in PCN, especially O-containing groups, providing a new insight for design heteroatoms-doped materials for solar energy conversion.