Nanocomposite Cathode Material Research Articles

Highly Stable Polyaniline-Based Cathode Material Enabled by Phosphorene for Zinc-Ion Batteries with Superior Specific Capacity and Cycle Life.

Aqueous zinc-ion batteries (ZIBs) are regarded as a type of promising energy-storage device because of their high safety and low cost, and polyaniline (PANI) is normally employed as a cathode material for ZIBs owing to its unique electrochemical properties and high environmental stability. However, a low specific capacity and a short cycle life limit the development and applications of PANI-based electrodes. Herein, we have developed a novel type of highly stable PANI-based cathode material enabled by phosphene (PR) for aqueous Zn-PANI batteries through in situ chemical oxidative polymerization. The introduction of PR nanoflakes not only inhibits the degradation of PANI and generates more active sites for Zn2+ storage but also enables a synergistic effect of the Zn2+ insertion/extraction and P-Zn alloying reaction. This promotes a high reversible specific capacity of 240.2 mAh g-1 at 0.2 A g-1 and excellent rate performance for the PR/PANI nanocomposite cathode material. Compared to the pristine PANI cathode material, the PR/PANI nanocomposite cathode material is more suitable for the Zn-PANI battery, thanks to its higher specific capacity and better cycle stability. This study provides an innovative approach for developing the next generation of reliable PR-based electrode materials for aqueous energy-storage devices.

Niobium sulfide nanocomposites as cathode materials for all-solid-state lithium batteries with enhanced electrochemical performance.

All-solid-state lithium batteries coupled with transition metal sulfide cathodes have gained significant attention due to their high energy density and exceptional safety. However, there are still critical challenges impeding their practical application, such as limited capacity delivery, weak ionic reaction kinetics and volume expansion. Herein, an a-NbS4/20%VGCF@15%Li7P3S11 nanocomposite cathode material is employed in all-solid-state batteries. A certain proportion of VGCF is introduced into crystalline NbS4 in order to mitigate the volume expansion and improve electronic conductivity. At the same time, a-NbS4/20%VGCF is in situ coated with a Li7P3S11 solid electrolyte layer to achieve an intimate interfacial contact. The obtained a-NbS4/20%VGCF@15%Li7P3S11 nanocomposite exhibits a remarkable electronic conductivity (1.0 × 10-1 S cm-1) and ionic conductivity (5.5 × 10-4 S cm-1), which are improved by five and two orders of magnitude compared to those of NbS4, respectively. The Li/Li6PS5Cl/a-NbS4/20%VGCF@15%Li7P3S11 battery exhibits a high initial discharge capacity of 1043.25 mA h g-1 at 0.1 A g-1. Even at 0.5 A g-1, it could provide a reversible capacity of 403.2 mA h g-1 after 500 cycles. This work provides a promising cathode material for all-solid-state lithium batteries with improved ionic/electronic conductivity, high reversible capacity and superior cycling stability.

Preparation and Characterization of Nanocomposite Perovskite Cathode Materials La0.3Sr0.7Fe0.4Ti0.6O3‐δ (LSFT) for Low‐Temperature SOFCs with Incorporation of Graphene Oxide (GO)

AbstractThe porous and mixed ionic electronic cathode conductor plays a vital role in the efficient working of low‐temperature solid oxide fuel cells. Perovskite composite cathode material La0.3Sr0.7Fe0.4Ti0.6O3‐δ (LSFT) is synthesized using the sol–gel method. Graphene oxide (GO) is integrated in 1 and 1.5 wt.% into the perovskite LSFT cathode to use as a cathode for low‐temperature solid oxide fuel cell (LT‐SOFC). Crystal structure analysis is studied by XRD and the crystalline size of samples is determined in the range of 103–73 nm. SEM analysis is used to characterize homogeneous and porous morphology. The FTIR spectral analysis is examined for proposed nanocomposite cathode materials. The electrical conductivities are carried out by four probe method in air atmosphere in the temperature range 300–600 °C and enhanced conductivity is obtained 7 Scm−1 for LSFT‐1.5 wt.% GO sample. For the same sample, a minimum value of area‐specific resistance (ASR) of 0.02 Ωcm2 is obtained. The performance of three‐layer fuel cells is tested by supplying H2 fueled at the anode and oxygen at the cathode terminal of the cell and peak power density is determined to be 362 mWcm−2 for GO incorporated fuel cell. The prepared cathode can be proposed as a potential candidate for low‐temperature solid oxide fuel cells.

Heteroatoms-doped carbon wrapped on T-Nb2O5 for high performance Mg-Li hybrid battery

Mg-Li hybrid batteries (MLHBs) are regarded as promising candidates for electrical energy devices because they can combine the high capacity as well as fast ion transfer advantages of cathodes in lithium-ion batteries (LIBs) and the great safety feature of Mg metal anode in MLHBs. Here, we report a core-shell nanocomposite cathode material (T-Nb2O5 @C-PZS) for MLHB application, where heteroatoms-doped carbon layer is wrapped on T-Nb2O5 microparticles. Owning to the excellent pseudocapacitive performance from T-Nb2O5 core and the abundant N, S and P heteroatoms from the carbon shell, the T-Nb2O5 @C-PZS cathode shows a high discharge capacity (198 mAh g−1 at 0.1 A g−1), excellent rate performance (100 mAh g−1 at 2 A g−1) and outstanding cyclic stability (a capacity retention rate of 85% after 5000 cycles at 1.0 A g−1), when the Mg metal is used as the anode. The advantages of the preparation, microstructure as well as electrochemical performance of T-Nb2O5 @C-PZS make it a promising cathode for MLHBs.

Nanocomposite Counter‐Electrode Materials for Dye‐Sensitized Solar Cells: A Review

To date, third‐generation solar‐electricity dye‐sensitized solar cells (DSSCs) are a hot research topic for the next generation of photovoltaic solar technology. Additionally, cathodes, including nanocomposite cathode‐based DSSCs, are a crucial component addition to the electrolyte anode. The usage of precious platinum (Pt) cathodes in DSSCs continues to be a barrier for large‐scale DSSCs manufacture. Finding a cost‐effective, environmentally benign, high power conversion efficiency (PCE), and electrocatalytic performance of an alternative Pt‐free nanocomposite cathode material in DSSCs is critical. This review focuses on recent developments in cathode materials, namely, nanocomposite cathodes like polymers/carbon, polymers/transition metal compounds (TMCs), and TMCs/oxide. Furthermore, it also includes the effect of fabrication methods on PCE, morphological structures, and electrocatalytic performance of nanocomposite cathodes in DSSCs, and finally, the conclusion and outlook.

Synergetic vanadium oxide nanocomposite cathode material with high specific capacity and long life for advanced aqueous zinc-ion batteries

Based on their high safety, low cost, and environmental friendliness aqueous zinc-ion batteries (AZIBs) are considered one of the most attractive candidates for large-scale energy storage applications. Vanadium-based compounds with high theoretical specific capacity are promising cathode materials for AZIBs. However, it is a great challenge for modified vanadium oxygen compounds to gain excellent zinc storage performance due to the strong electrostatic interaction between Zn2+ and V, O. Here, we present a one-step hydrothermal method and subsequent calcination to gain an advanced V2O5/VO2 nanocomposite as the cathode of highly stable AZIBs. The obtained composite has a synergistic effect, and the introduction of VO2 enhances the composites' general characteristics. Therefore, this composite structure not only accelerates the intercalation dynamics of Zn2+, but also further consolidates the stability during cycling. As a result, the as-synthesized cathode provides a high specific capacity of 453.2 mA h g−1 at 1 A g−1 and excellent cycle stability, with a high capacity maintained (200 mA h g−1) over 80 % after 2000 cycles at 10 A g−1. This work provides a new perspective for the development of viable insertion materials for AZIBs.

Lithium Sulfide –Carbon Composite Use as Positive Electrode in Post Lithium Ion Batteries Technology

Li‐ion batteries (LIBs) are the powerhouse for the electronic devices in this modern mobile society, and enabler of the current communication revolution. Consumers demands advanced electronics and sustainable industries in general. To satisfy these demands, the new generation of rechargeable batteries need to provide much higher energy and power density than the actual technology. Commercial LIBs consist of lithium cobalt oxide as positive electrodes and graphite as a negative electrode, this system has energy density values ca. 250 WhL-1.Lithium-sulfur is commonly considered as one of the most promising chemistries for improve traditional lithium-ion batteries in weight sensitive applications due to high theoretical capacity of lithium sulfide (Li2S) and high gravimetric energy density of such cells. Li2S provides a promising route for lithium storage due to high theoretical specific capacity (1166 mAh g−1). This positive electrode material can be coupled with lithium-free negative electrode to develop high-energy-density batteries; this can improve the safety of the devices. Li2S is significantly more thermally stable, and offer greater mechanical stability as no further volumetric expansion occurs upon cycling.Li2S particles must be handled only in inert atmospheres (making production of high-performance cathode materials, on a commercial scale, quite difficult) and suffer from rapid degradation in cells during cycling. There are still challenges with it (e.g., low conductivity, high over potential and irreversible polysulfide diffusion), which have prevented the S utilization and stability. The dissolved polysulfides deposit on the surface of both electrodes resulting in a rapid impedance growth, loss in active material and ultimately battery failure.The complex synthesis method of Li2S–carbon composites restrains the large-scale productivity. We propose an easy and time saving method to synthesize a Li2S based nanocomposite cathode material by wet milling.This work may shed fresh insight into bridging the huge gap between high energy and safety of rechargeable cells for feasible applications. Figure 1

Evaluation of the electrocatalytic performance of a novel nanocomposite cathode material for ceramic fuel cells

Cathode materials are pivotal in advancing ceramic fuel cell (CFC) technology. However, they still suffer from insufficient oxygen reduction reaction (ORR) activity and a high thermal expansion coefficient (TEC). In this study, we develop a thermodynamically stable self-ordered nanocomposite cathode material with the unique composition, BaCo0.5Ce0.3Fe0.1Yb0.1O3-δ (BCCFYb). Upon calcination, the precursor material separates into a host cubic and ancillary rhombohedral phase. We compare the performance of the triple ionic and electronic (O2−/H+/e−) conducting BCCFYb to that of cobalt-rich oxide-ion and electron (O2−/e−) conducting BaCo0.833Yb0.167O3-δ (BCYb), cerium-rich proton and electronic (H+/e−) conducting BaCe0.75Fe0.25O3-δ (BCF), and Co–Ce-rich triple ionic and electronic (O2−/H+/e−) conducting BaCo0.833Yb0.167O3-δ - BaCe0.75Fe0.25O3-δ (BCYb-BCF) traditional composite materials. The BCCFYb demonstrates a low TEC, good operational stability, and superior cathodic performance in both oxygen ion- and proton-conducting CFC modes, making it a promising cathode material for ceramic fuel cells.

Synthesis and Electrical Characterizations of Graphene Oxide Incorporated Nanocomposite Cathode Materials for Low Temperature SOFCs

Synthesis and Electrical Characterizations of Graphene Oxide Incorporated Nanocomposite Cathode Materials for Low Temperature SOFCs

Structural, electric and dielectric properties of perovskite based nanoparticles for energy applications

Abstract A nanocomposite electrode, obtained by combining two high performance perovskite materials, such as lanthanum strontium cobalt ferrite, La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) and gadolinium doped ceria, Ce0.85Gd0.15O1.5 (GDC), were investigated as a promising cathode for moderate temperature solid oxide fuel cells (SOFCs). The synthesized material has good conductivity and catalytic performance. The purpose of this synthesis was to prepare a stable and highly performing nanocomposite cathode material. In this research work, LSCF and GDC were separately synthesized by co-precipitation and solid-state reaction method to gain a homogeneous perovskite phase. Varying concentrations of LSCF–GDC composite with GDC (10 wt.%, 20 wt.% and 30 wt.%) were synthesized followed by calcination at 600 °C to remove water content and to achieve an adequate porous structure for oxygen absorption and desorption. These fabricated LSCF, GDC, and the nanocomposite specimens were characterized for microstructure, particle size etc. via. X-ray diffraction method (XRD), scanning electron microscope (SEM) and the laser particle size analyzer. This procedural approach helps to expand new methods for generating bi-functional duel nano-sized perovskites with great performance and stability which can be utilized for advancement of renewable energy sectors especially for rechargeable fuel batteries.

Structural, electric and dielectric properties of perovskite based nanoparticles for energy applications

Abstract A nanocomposite electrode, obtained by combining two high performance perovskite materials, such as lanthanum strontium cobalt ferrite, La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) and gadolinium doped ceria, Ce0.85Gd0.15O1.5 (GDC), were investigated as a promising cathode for moderate temperature solid oxide fuel cells (SOFCs). The synthesized material has good conductivity and catalytic performance. The purpose of this synthesis was to prepare a stable and highly performing nanocomposite cathode material. In this research work, LSCF and GDC were separately synthesized by co-precipitation and solid-state reaction method to gain a homogeneous perovskite phase. Varying concentrations of LSCF–GDC composite with GDC (10 wt.%, 20 wt.% and 30 wt.%) were synthesized followed by calcination at 600 °C to remove water content and to achieve an adequate porous structure for oxygen absorption and desorption. These fabricated LSCF, GDC, and the nanocomposite specimens were characterized for microstructure, particle size etc. via. X-ray diffraction method (XRD), scanning electron microscope (SEM) and the laser particle size analyzer. This procedural approach helps to expand new methods for generating bi-functional duel nano-sized perovskites with great performance and stability which can be utilized for advancement of renewable energy sectors especially for rechargeable fuel batteries.

Facile Synthesis of LiMn0.75Fe0.25PO4/C Nanocomposite Cathode Materials of Lithium-Ion Batteries through Microwave Sintering

Facile Synthesis of LiMn0.75Fe0.25PO4/C Nanocomposite Cathode Materials of Lithium-Ion Batteries through Microwave Sintering

Chemically Synthesised ϒ-MnO2, and β-MnO2/Single Wall Carbon Nanotube Composites As a Promising High Capacity Cathode Materials for Lithium-Ion Batteries

This work reports the ϒ-MnO2, and β-MnO2 single wall carbon nanotube (SWCNT) nanocomposite cathode material synthesised successfully by chemical method for lithium-ion batteries. The electrochemical properties galvanostatic charge-discharge, cycle ability, rate performance and cyclic voltammetry were greatly enhanced by using the (SWCNT) composite cathode as a comparison to the pristine ϒ-MnO2, and β-MnO2. As a consequence, the modified (SWCNT) composite cathode material exhibits superior initial discharge capacity 255 mAh g-1 at 0.1C with coulombic efficiency of 99.22% and 118 mAh g-1 at 1C with a capacity retention (coulombic efficiency) of 95.5% (99.9%) after 100 cycles in the potential window of 2.0-4.5V (vs Li/Li+). In comparison pristine β-MnO2 exhibit only 169 mAh g-1 at 0.1C, corresponding to lower initial coulombic efficiency of 97% and 73 mAh g-1 at 1C with capacity retention (coulombic efficiency) of 71.4% (92%) after 100 cycles. The significant improvement in the de-/lithiation kinetic can be accredited to the enhancement in apparent lithium ion diffusion coefficient and electronic conductivity making it more applicable in high power commercialization.

Dual-Phase Nanocomposite Cathode Materials for Low-Temperature Protonic Ceramic Fuel Cells

Due to the relative low activation energy, protonic ceramic fuel cells (PCFCs) have attracted increasing attention in recent years because of the efficient low-temperature (LT, 300-600oC) operation. However, the insufficient LT activity of cathode materials for oxygen reduction reaction (ORR) is still one of the significant challenges to achieve excellent performance. It has been recognized that the triple conductivity (electron, oxygen ion, and proton) are prerequisite properties for a high-performance PCFC cathode. Many strategies on material selection have already been done to meet this requirement. BaCo0.4Fe0.4Zr0.1Y0.1O3-δ (BCFZY0.1) was reported as a single-phase triple conducting oxide cathode material which provides improvement of cell performance. However, the pure phase in return limits the further adjustment of the triple conductivities. The composite structures comprised proton conducting oxide and mixed ionic and electronic conducting can also introduce triple conductivity for cathode materials. Unfortunately, traditional fabrication methods for these composites are limited by mechanical mixing with two or more components, which significantly restricted contact sites/areas of different components and further obstacle ORR performance. Thus, the nanocomposite cathodes are demanded with high phase connection and flexible phase adjustment. Herein, the modified Pechini method was utilized to synthesize nanocomposite materials comprised of a mixed ionic and electronic conducting cubic perovskite phase and a protonic conducting orthorhombic perovskite phase from a nominal composition of BaCe0.4Fe0.4Co0.2O3-δ (BCFC). This one-pot method not only increased the density of the activated sites/areas for ORR by decreasing grain sizes for each phase but also provided excellent thermodynamic stability because the solid-state reaction thermodynamic equilibrium has arrived during synthesis. BCFC was confirmed to be a new promising nanocomposite cathode material for LT-PCFCs.

CuCl2-Based Cathode Material with Incombustible Inorganic Liquid Electrolyte Towards Room-Temperature Na Rechargeable Battery

Na rechargeable batteries have gained much attention as an alternative power sources of Li rechargeable batteries. Nevertheless, further advance on Na rechargeable batteries is necessary, to compete in rechargeable battery market because of their low energy density and reliability. Here, we demonstrate a new type of room temperature Na rechargeable battery which employs CuCl2/C nanocomposite cathode material and SO2-based inorganic liquid electrolyte. A high discharge capacity of 200 mAh g−1 corresponding to theoretical energy density of 580 Wh kg−1 is achieved, and also a high round-trip energy efficiency (>96%) and excellent cycle-life over 1000 cycles, which has never been obtained in conventional organic electrolyte system. The remarkable electrochemical performance is mainly attributed to the use of the non-flammable SO2-based electrolyte, which guarantees a reversible conversion reaction between CuCl2 and CuCl with NaCl. Further, detailed reaction mechanism of the new battery system will be discussed in the presentation.

Chemical Origins of Electrochemical Overpotential in Surface‐Conversion Nanocomposite Cathodes

AbstractA new branch of promising nanocomposite cathode materials for rechargeable batteries based on non‐intercalation materials has been recently discovered. However, all the nanocomposite cathodes reported thus far suffer from a large overpotential in the first charge, which hinders the activation and lowers the energy efficiency. Here, a series of model nanocomposites consisting of MnO and various metal fluorides (LiF, NaF, KF, RbF, CsF, MgF2, CaF2, and AlF3) to identify the key parameters affecting the activation and overpotential in the first charge are evaluated. It is demonstrated that the F 1s binding energy of the metal fluorides is a plausible indicator of the overpotential in the first charge as well as the subsequent reversible discharge capacity. The stability of the cation in the electrolyte and its solvation nature are also shown to affect the overall activation process. Finally, it is proposed that appropriate tuning of the binding energy of metal fluorides (e.g., by forming solid solutions such as LiCsF2) is a feasible approach to reduce the overpotential and increase the reversible capacity. The findings broaden the current understanding of surface‐conversion nanocomposite chemistries, thus providing guidelines for the design of nanomixture cathode materials for rechargeable batteries.

Characterization of carbon-coated LiFe0.3Mn0.7PO4 particles produced using a colloidal method for lithium batteries

A convenient colloidal process for the preparation of LiFe0.3Mn0.7PO4/C nanocomposite cathode material for lithium batteries is reported. The process involves the use of lithium dihydrogen phosphate (LiH2PO4), ferrous chloride (FeCl2) and manganese chloride (MnCl2) as starting materials, with anhydrous N-methylimidazole (NMI) as the solvent and carbon source, followed by a 3 h annealing step at 650 °C. Carbonization of the molten salt NMIH+Cl− derived from NMI resulted in 3.0 wt% carbon content in the LiFe0.3Mn0.7PO4/C with 3–6 nm thick carbon coating. The material was characterized by thermogravimetric and differential thermal analysis, differential scanning calorimetry, powder X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, atomic absorption spectroscopy, Raman spectroscopy, four-point probe method, cyclic voltammetry and galvanostatic cycling experiments in coin cells. SEM analysis of the LiFe0.3Mn0.7PO4/C material revealed non-spherical agglomerates with average width and length of 50–70 nm and 120–150 nm, respectively. The electronic conductivity of carbon-coated LiFe0.3Mn0.7PO4 was found to be 9.7 × 10−2 S cm−1 at room temperature, and the discharge capacity reached 137 mAh g−1 measured at C/20 when the cell was cycled between 2.2 V and 4.2 V vs. Li+/Li, and 124 mAh g−1 at C/10 for the first cycle. The capacity dropped to 122 mAh g−1 at C/10 after the first 25 cycles and then stayed constant at 121 mAh g−1 until the 100th discharge cycle, making this cell to exhibit excellent cycling stability with only a 2.4% decrease.

Enhanced electrochemical performance of W incorporated VO2 nanocomposite cathode material for lithium battery application

We report the synthesis, characterization, and performance evaluation of tungsten (W) incorporated vanadium oxide (VO2) nanocomposite cathode material for improved lithium storage performance. VO2 nanorods, 100–200 nm in diameter and 1–3 μm in length are synthesized using a hydrothermal method. W incorporation at different weight percent results in the VO2 morphology shifting from rods to a sheet type structure. The lithium storage performance of VO2 has improved remarkably by increasing the loading of W to an optimal level, which influence the intercalation/ deintercalation of lithium ions into the expanded lattices of VO2. The maximum specific capacity observed for the optimal VO2/W4 composite was 381 mAh/g at a current density of 0.1 C. Cyclic voltammetry measurements showed the presence of an electroactive V3+/V4+ redox couple, leading to lower peak separation and voltage polarization differences. Superior charge storage performance was observed with the VO2/W4 composite as compared to the VO2 based devices.

Facile Synthesis of Uniform Carbon Coated Li2S/rGO cathode for High-Performance Lithium-Sulfur Batteries

ABSTRACTLithium sulfide (Li2S) is one of the most attractive cathode materials for high energy density lithium batteries as it has a high theoretical capacity of 1166 mA h g-1. However, Li2S suffers from poor rate performance and short cycle life due to its insulating nature and polysulfide shuttle during cycling. In this work, we report a facile and viable approach to address these issues. We propose a method to synthesize a Li2S based nanocomposite cathode material by dissolving Li2S as the active material, polyvinylpyrrolidone (PVP) as the carbon precursor, and graphene oxide (GO) as a matrix to enhance the conductivity, followed by a co-precipitation and high-temperature carbonization process. The Li2S/rGO cathode yields an exceptionally high initial capacity of 817 mAh g-1 based on Li2S mass at C/20 rate and also shows a good cycling performance. The carbon-coated Li2S/rGO cathode demonstrates the capability of robust core-shell nanostructures for different rates and improved capacity retention, revealing carbon coated Li2S/rGO composites as an outstanding system for high-performance lithium-sulfur batteries.

High Performance Na–CuCl2 Secondary Battery Using Sulfur Dioxide Based Inorganic Liquid Electrolyte

Na rechargeable batteries have gained much attention as alternative power sources to replace Li rechargeable batteries. However, Na rechargeable batteries need to be further advanced to successfully penetrate rechargeable battery market because of their low energy density and poor reliability. Here, we demonstrate a new type of room temperature Na rechargeable battery that employs CuCl2/C nanocomposite cathode material and SO2-based inorganic liquid electrolyte. The cell delivered a high discharge capacity of 200 mAh g−1, corresponding to a theoretical energy density of 580 Wh kg−1. It also showed a high round-trip energy efficiency (>96%) and remarkable cycle-life over 1000 cycles, which has never been obtained in an organic electrolyte system. These excellent electrochemical performances are mainly attributed to the use of the SO2-based electrolyte, which guarantees a reversible conversion reaction between CuCl2 and CuCl with NaCl. The detailed reaction mechanism of this new battery system will be also discussed in this presentation.