Excellent Charge-discharge Performance Research Articles

Flexible supercapacitors based on carbon fiber cloth coated copper hexacyanoferrate nanoparticles as positive electrode material

Herein, we report fabrication of a new electrode material based on copper(II) hexacyanoferrate(II) nanoparticles coated on flexible and light weight carbon fiber cloth (CuHCF-NPs@CC) for supercapacitors application. Uniform spherical CuHCF-NPs are successfully synthesized through a simple chemical co-precipitation technique at ambient temperature. The CuHCF-NPs were physically examined by different characterizations, for example, FT-IR, UV–Visible, Raman, XRD, XPS, FE-SEM, EDAX and TEM. The CuHCF-NPs@CC is an excellent electrode material that has an open framework structure that can accommodate a wide variety of ions. The electrochemical characteristics of pseudocapacitive behavior of the material were characterized by cyclic voltammogram (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) on two different electrolytes such as K2SO4 and Na2SO4. The CuHCF-NPs@CC exhibits a good reversible cycle in the range of 0 to 0.9 V and excellent charge-discharge performance with a specific capacity of 42.96C g−1 and 24.2C g−1 at 0.2 A g−1 of current density in K2SO4 and Na2SO4 electrolyte, respectively. The low cost, simple preparation methodology, and an outstanding electrochemical behavior of CuHCF-NPs@CC considering a viable candidate for the future energy storage system.

Water-soluble Polypyrrole-Polybis(4-oxy benzene sulfonic acid)phosphazene Composites and Investigation of Their Performance as Cathode Binder in Li-ion Batteries.

Current electric storage systems eagerly focus on high-power and energy-dense Lithium-ion batteries to cope with increasing energy storage demands. Since cathode materials are one of the bottlenecks of these batteries, there is much interest in layered lithium-rich manganese oxide-based (LLMO) cathodes which can develop this technology. However, Initial Coulombic Efficiency (ICE) loss, poor rate performance and cycling instability issues are still persistent as problems to be solved for these materials. Recent research shows that water-soluble binders are effective in improving the performance of LLMO materials. Herein, we describe the synthesis, characterisation, and application of a series of water-soluble composites as a binder for LLMO cathodes. The PPy is introduced as part of the binder to improve the electronic conductivity and two different oxidants and various PPy to PSAP ratios were used to optimise the final properties. The electrochemical performance and morphology of the cathodes before and after cycling were investigated and compared with the conventional PVDF binder. The LLMO-2c electrode showed excellent charge-discharge performance, especially at 5 C and 10 C rates, and high cycling stability at 0.2 C whilst maintaining a final capacity of 184 mAh/g after 200 cycles, which is equal to 89.3 % capacity retention.

Prussian blue analogue derived from leather waste as a bifunctional catalyst in zinc-air batteries.

A Prussian blue analogue was synthesized using biomass leather waste as a precursor by doping with Co2+ ions. This material, demonstrates good performance in both the oxygen reduction reaction and oxygen evolution reaction, and exhibits excellent charge-discharge performance and stability in zinc-air batteries.

A 3d-4d-5d High Entropy Alloy as a Bifunctional Oxygen Catalyst for Robust Aqueous Zinc-Air Batteries.

High entropy alloys (HEAs) are highly suitable candidate catalysts for oxygen evolution and reduction reactions (OER/ORR)as they offer numerous parameters for optimizing the electronic structure and catalytic sites. Herein, FeCoNiMoW HEA nanoparticles are synthesized using a solution-based low-temperature approach. Such FeCoNiMoW nanoparticles show high entropy properties, subtle lattice distortions, and modulated electronic structure, leading to superior OER performance with an overpotential of 233mV at 10mAcm-2 and 276mV at 100mAcm-2 . Density functional theory calculations reveal the electronic structures of the FeCoNiMoW active sites with an optimized d-band center position that enables suitable adsorption of OOH* intermediates and reduces the Gibbs free energy barrier in the OER process. Aqueous zinc-air batteries (ZABs) based on this HEA demonstrate a high open circuit potential of 1.59V, a peak power density of 116.9mWcm-2 , a specific capacity of 857mAhgZn -1 , and excellent stability for over 660h of continuous charge-discharge cycles. Flexible and solid ZABs are also assembled and tested, displaying excellent charge-discharge performance at different bending angles. This work shows the significance of 4d/5d metal-modulated electronic structure and optimized adsorption ability to improve the performance of OER/ORR, ZABs, and beyond.

Achieving high comprehensive energy storage properties of BNT-based ceramics via multiscale regulation

It is difficult to obtain high polarization strength and high breakdown strength synchronously, resulting in the drawback of lower energy storage density, which inhibits commercial application of energy storage materials. We have successfully prepared (1-x)(0.93Bi0.5Na0.5TiO3-0.07CaSnO3)-xSrTiO3 (BNT–CS–xST) ceramics by solid-state method. The presence of polymorphic nanodomains and the large electric displacement generated by the high charge Sr2+-Sr2+ ion pairs help to delay saturation polarization (Pm ∼ 48.64 μC/cm2 at 315 kV/cm). In addition, the breakdown field strength (Eb) is increased by grain refinement and increasing the band gap. It is noteworthy that a high recoverable energy storage density (Wrec = 4.2 J/cm3) and a great efficiency (η = 88%) were achieved simultaneously in BNT–CS–0.5ST ceramic. Moreover, excellent charge-discharge performance was also achieved, with a discharge energy density Wd of 2.2 J/cm3, a current density CD of 1724 A/cm2 and a power density PD of 250 MW/cm3. The study demonstrates that the great potential of BNT–CS–xST ceramics in power storage devices and provides an effective strategy for designing ceramics dielectric capacitors with excellent performance.

Achieving high energy storage density in BaTiO3- (Bi0.5Li0.5)(Ti0.5Sn0.5)O3 lead-free relaxor ferroelectric ceramics

New environmental protection energy storage devices have been widely studied in recent years. BaTiO3-based ceramics are considered excellent materials for achieving high energy storage due to their exceptional dielectric and ferroelectric properties. In this study, a series of (1-x)BaTiO3-x(Bi0.5Li0.5)(Ti0.5Sn0.5)O3 (xBLST, x = 0.1, 0.15, 0.2, and 0.25) ceramics were successfully synthesized by the conventional solid-phase method. The 0.2BLST ceramics exhibited a high recoverable energy storage density (Wrec) of 3.83 J/cm3 and high energy storage efficiency (η) of 88 % under the breakdown strength (Eb) of 525 kV/cm. Moreover, the Wrec of 0.2BLST ceramics had outstanding stability over 1–120 Hz and between 20 and 180 °C. Finally, the 0.2BLST ceramics displayed excellent charge–discharge performance with a discharge power of up to 86 MW/cm3, a high discharge density of 0.68 J/cm3, and an extremely fast discharge time (t0.9∼71 ns). These properties establish that 0.2BLST ceramic is a promising lead-free energy material.

A Zinc-Ion Battery-Type Self-Powered Pressure Sensor with Long Service Life.

Accurate and continuous pressure signal detection without external power supply is a key technology to realize the miniaturization of wearable electronic equipment, the internet of things, and artificial intelligence. However, it is difficult to be achieved by using current sensor technologies. Here, a new one-body strategy, i.e., zinc-ion battery pressure (ZIB-P) sensor technology, which designs the rechargeable solid-state ZIB itself as a flexible pressure sensor is reported. In the device, an isolation layer is introduced into the sandwich configuration solid-state battery to realize the change of device internal resistance by pressure during the transformation of the mechanical signal to the electrical signal. This battery pressure sensor possesses good flexibility, fast response/recovery time (76.0/88.0ms), stable long-term response, excellent cycle stability (100 000 times), and wide pressure detection range (2.0 to 3.68 × 105 Pa). Especially, the excellent charge-discharge performance in the ZIB-P sensor endows it with the real-time detection ability of human vital signs (pulse, limb movement, etc.) and ultrahigh stability without degradation even under 100 000 times pressure stimulation. The ZIB-P sensor strategy provides a new solution for the future development of miniaturized wearable electronic devices.

Study on flexible thin air electrodes and electrochemical performance of LR6 size as well as pouch Zn-air cells

Manufacturing stable and thin air electrodes for flexible Zn-air batteries becomes increasingly important and remains challenge. Here, we report low-cost mechanical calendering to fabricate thin gas-diffusion layers (GDL), catalytic layers (CL) and then heat pressing together. Finally, cylindrical and other sizes of flexible air electrodes are produced without the use of commercially expensive carbon cloth or carbon papers. By assembling the flexible air cathodes with anode Zn-In-Bi alloy powders or Zn foils, alkaline gel electrolytes and membranes, two kinds of Zn-air cells are assembled for performance evaluation. Results reveal that the LR6 Zn-air cells show a capacity of 5300–5400 mAh and an energy density of 340 Wh·kg−1 at 100 mA, having a double discharge capacity compared to the same size alkaline ZnMnO2 cells. Under a high drain rate of 1000 mA, the capacity and utilization of the Zn alloy powder remain 2750 mAh and 372 mAh·g−1, respectively. The flexible pouch Zn-air cells exhibit excellent charge-discharge performance under conditions of each cycle with 10 min at 2 mA cm−2. The discharge voltage is maintained in the range of 1.25–1.30 V within 120 cycles while the charge voltage is 2.00–2.05 V. These results demonstrate that the thin air cathodes can satisfy the high bending requirements for cylindrical LR6 size cells and flexible pouch Zn-air cells, as well as have high mechanical stability and electrochemical performance. Electrochemical impedance spectroscopies of the air cathodes and Zn-air cells are also examined.

Energy storage and charge-discharge performance of B-site doped NBT-based lead-free ceramics

Dielectric ceramic materials with high energy-storage density and excellent charge-discharge performance are desirable for use in dielectric capacitors. In this study, (Na 0.5 Bi 0.5 ) 0.75 Sr 0.25 TiO 3 – x Nb 2 O 5 (denoted as NBSTN x ) lead-free ceramics were prepared by a solid-state reaction method. Polarization-electric field hysteresis loops ( P–E loops) reflected the energy storage characteristics of the NBSTN x ceramics. Introducing Nb into a pure NBST ceramic can reduce the large remnant polarization ( P r ) and make the P–E loops slimmer. Through repeated trials and calculations, the maximum recoverable energy-storage density ( W rec ~ 3.25 J/cm 3 ) and energy storage efficiency ( η ~ 74.5%) were achieved for the NBSTN 0.03 ceramic at 140 kV/cm. We also tested the stability performance of the NBSTN x ceramics, where the NBSTN 0.03 ceramic exhibited the highest thermal stability (30–100 °C) and frequency stability (10–1000 Hz). The NBSTN 0.03 ceramic also had a fast discharge rate (<300 ns) and a good discharge energy-storage density ( W d ~ 1.80 J/cm 3 ). Therefore, the NBSTN 0.03 ceramic with a good energy-storage density and charge-discharge performance has excellent application prospects for practical dielectric capacitors. • A strategy incorporating B-site doping to enhance energy storage performance. • A relatively high W rec of 3.25 J/cm 3 and η of 74.5%. • Sample with 0.03 mol Nb doping shows relatively good temperature and frequency stability.

Phase engineering in NaNbO3 antiferroelectrics for high energy storage density

The NaNbO3 antiferroelectrics have been considered as a potential candidate for dielectric capacitors applications. However, the high-electric-field-unstable antiferroelectric phase resulted in low energy storage density and efficiency. Herein, good energy storage properties were realized in (1-x)NaNbO3-xNaTaO3 ceramics, by building a new phase boundary. As a result, a high recoverable energy density (Wrec) of 2.2 J/cm3 and efficiency (η) of 80.1% were achieved in 0.50NaNbO3-0.50NaTaO3 ceramic at 300 kV/cm. The excellent energy storage performance originates from an antiferroelectric-paraelectric phase boundary with simultaneously high polarization and low hysteresis, by tailoring the ratio of antiferroelectric and paraelectric phases. Moreover, the 0.50NaNbO3-0.50NaTaO3 ceramic also exhibited good temperature and frequency stability, together with excellent charge-discharge performance. The results pave a good way of designing new NaNbO3-based antiferroelectrics with good energy storage performance.

Construction of iron doped cobalt- vanadate- cobalt oxide with metal-organic framework oriented nanoflakes for portable rechargeable zinc-air batteries powered total water splitting

The exploration of highly efficient, cost-effective, long-term sustainable oxygen reduction, oxygen evolution, and hydrogen evolution electrocatalysts is crucially important to the production of renewable energy storage and conversion applications, including fuel cells and rechargeable zinc-air batteries. Herein, a trifunctional electrocatalyst based on iron-doped metal-organic framework assisted cobalt vanadate integrated with cobalt oxide (Fe doped MOF [email protected] nanoflakes) is described in a facile synthetic approach. This synthetic strategy provides a unique nanoflakes heterostructure, an abundant porous structure, high specific surface area, and extremely large active sites. Additionally, the nitrogen element is also incorporated into the MOF scaffold during the pyrolysis under the nitrogen environment, greatly facilitating the electrochemical behavior. The prepared Fe doped MOF [email protected] nanoflakes catalysts possess excellent and stable electrochemical activity for ORR, OER, HER, and overall water splitting reaction. The rechargeable zinc-air battery is fabricated using Fe doped MOF [email protected] nanoflakes as an air cathode having excellent charge-discharge performance and high cyclic stability. Eventually, the developed zinc-air battery is used as self-power water splitting for the overall water splitting under room temperature. This study creates new opportunities for the fabrication of advanced earth-abundant electrocatalysts for electrochemical energy-related applications.

High breakdown strength and enhanced energy storage performance of niobate-based glass-ceramics via glass phase structure optimization

The dielectric capacitors with excellent energy storage characteristics, high power density and temperature stability are strongly desired in modern pulse power system and electronic industry. Thus, BKNAS-xPbO glass-ceramics were designed and prepared. Free oxygen in the glass phase which weakens the glass network structure can be adsorbed by trace Pb2+, thus improving the breakdown strength (BDS) of BKNAS glass-ceramics. Extremely high BDS (~2089 kV/cm) and excellent energy storage density (~17.62 J/cm3) were achieved in 0.6 mol% PbO doped BKNAS glass-ceramics. Moreover, the permittivity variance of BKNAS-0.6PbO glass-ceramics was less than 4.39% in the ultrawide temperature range (−80–300 °C), suggesting excellent temperature stability. The single layer capacitor made by BKNAS-0.6PbO glass-ceramics also exhibited excellent charge-discharge performance, in which the underdamped discharge power density reached 133.69 MW/cm3 as well as the overdamped discharge power density reached 146.89 MW/cm3 with ultrashort discharge time (<18 ns). The above results show that BKNAS-0.6PbO glass-ceramics possesses great potentiality for pulse capacitors owning to excellent energy storage property, temperature stability and charge-discharge performance.

Synergistic effects of flake-like ZnO/SnFe2O4/nitrogen-doped carbon composites on structural stability and electrochemical behavior for lithium-ion batteries

In order to improve the electrochemical performance and relieve volume expansion of pure SnFe2O4 anode for lithium-ion batteries (LIBs), we synthesized a novel ZnO/SnFe2O4/nitrogen-doped carbon composites (ZSFO/NC) with flake-like polyhedron morphology by using ZIF-8 as a sacrificial template. Remarkably, it exhibited an initial charge/discharge capacities of 1078.3/1507.5 mAh g−1 with a high initial coulombic efficiency (ICE) of 71.2%, and maintained a steady charge/discharge capacities of 1495.7/1511.8 mAh g−1 at 0.2 A g−1 after 300 cycles. The excellent rate performance of 435.6 mAh g−1 at a higher current density of 10.0 A g−1 and superior reversible capacity of 532.3/536.2 mAh g−1 after 500 cycles at 2.0 A g−1 were obtained. It revealed that the nitrogen-doped carbon matrix and peculiar structure of ZSFO/NC not only effectively buffered large volume expansion upon (de)lithiation through the synergistic interface action between ZnO, SnFe2O4 and NC, but also improved capacity of the composite by large contribution of surface pseudo-capacitance. The excellent charge–discharge performance showed that ZSFO/NC composite has a great potential for LIBs due to the synergistic effect of the multi-components.

The Development of Si Anode Materials by Nanotechnology for Lithium-ion Battery

Nowadays, lithium-ion batteries (LIBs) are applied in many fields for their high energy density, low cost, and long cycle life, highly appreciated in a commercial application. Anode materials, a vital factor contributing to high specific capacity, have caught great attention in next-generation LIBs development. Silicon (Si) has been generally considered one of the best substitutes for the commercial carbon-based anodes of lithium-ion batteries due to its extremely high theoretical capacity, excellent charge-discharge performance, and low cost compared with other anode materials. In this review, various silicon-based materials, including nanostructured silicon and silicon composite materials, are summarized, and both advantages and challenges are analyzed. The article emphasizes the remarkable electrochemical characteristics and significant improvement of battery performance by applying nanostructure and silicon composites conjugates. Besides, the challenges and outlook on the nanostructure design of Si and silicon composites are presented.

High energy storage density with high power density in Bi0.2Sr0.7TiO3/BiFeO3multilayer thin films

A novel Bi0.2Sr0.7TiO3/BiFeO3thin film prepared by sol–gel/spin coating possesses ultrahigh energy storage density, good thermal stability and excellent charge-discharge performance.

Exploring the Efficient Na/K Storage Mechanism and Vacancy Defect-Boosted Li+ Diffusion Based on VSe2/MoSe2 Heterostructure Engineering.

As typical 2D materials, VSe2 and MoSe2 both play a complementary role in Li/Na/K storage. Therefore, we designed and optimized the VSe2/MoSe2 heterostructure to gain highly efficient Li/Na/K-ion batteries. Most importantly, achieving fast Li/Na/K-ion diffusion kinetics in the interlayer of VSe2/MoSe2 is a key point. First of all, first-principles calculations were carried out to systematically investigate the packing structure, mechanical properties, band structure, and Li/Na/K storage mechanism. Our calculated results suggest that a large interlayer spacing (3.80 Å), robust structure, and metallic character pave the way for achieving excellent charge-discharge performance for the VSe2/MoSe2 heterostructure. Moreover, V and Mo ions both suffer a very mild redox reaction even if Li/Na/K ions fill the interlayer space. These structures were all further verified to show thermal stability (300 K) by means of the AIMD method. By analyzing the Li/Na/K diffusion behavior and the effect of vacancy defect on the structural stability and energy barrier for Li interlayer diffusion, it is found that the VSe2/MoSe2 heterostructure exhibits very low-energy barriers for Na/K interlayer diffusion (0.21 eV for Na and 0.11 eV for K). Compared with the VSe2/MoSe2 heterostructure, the V0.92Se1.84/MoSe2 heterostructure not only can still maintain a stable structure and metallic character but also has much lower energy barrier for Li interlayer diffusion (0.07 vs 0.48 eV). These discoveries also break new ground to eliminate the obstacles preventing Li+ diffusion in the interlayer of other heterostructure materials. Besides, both VSe2/MoSe2 and V0.92Se1.84/MoSe2 heterostructures have low average open-circuit voltage (OCV) values during Li/Na/K interlayer diffusion (1.07 V for V0.92Se1.84/MoSe2 vs Li+, 0.86 V for VSe2/MoSe2 vs Na+, and 0.54 V for VSe2/MoSe2 vs K+), such low OCV values are beneficial for anode materials with excellent electrochemical properties. The above findings offer a new route to design anode materials for Li/Na/K-ion batteries.

FeCo alloy/N, S dual-doped carbon composite as a high-performance bifunctional catalyst in an advanced rechargeable zinc-air battery

Abstract The rational design and development of cost-effective, high-performance, and stable bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalysts are essential for rechargeable zinc-air batteries. Herein, a novel FeCo composite composed of alloy nanoparticles embedded in an N, S dual-doped carbon matrix (FeCo/NSC) was prepared via one-step carbonization of amphiphilic dodecanethiol-metal salts wrapped in carbon nitride (C3N4). The compact combination of dual metal-alloys and dual-doped carbon endowed the composite with the active sites for the ORR and OER, achieving efficient electrical transmission and highly efficient bifunctional catalytic performance. The obtained FeCo-1/NSC catalyst exhibited excellent electrocatalytic activity with a half-wave potential of 0.82 V (vs. RHE) for the ORR and a low overpotential of 0.325 V at 10 mA cm−2 for the OER. The liquid Zn-air battery with FeCo-1/NSC as an air electrode displayed excellent charge-discharge performance, high power density, and robust charge-discharge stability for 150 h compared to the 20% Pt/C + RuO2 counterpart. Furthermore, the FeCo-1/NSC-based flexible solid-state Zn-air battery exhibited a higher power density and good charge-discharge stability over 10 h of operation. Thus, a promising strategy for bifunctional electrocatalyst development as part of rechargeable and wearable Zn-air batteries was provided.

Electrospun ZnCo2O4/C composite nanofibers with superior electrochemical performance for supercapacitor

In recent years, supercapacitors have attracted much attention due to their excellent charge–discharge performance, long-term cycle lifetimes, and high specific power. Transition metal oxides are promising candidates for environmentally friendly, low-cost, and high-powered energy storage materials. In addition, the use of one-dimensional nanostructures can markedly enhance the characteristic properties of the transition metal oxides. In this work, ZnCo2O4/C composite nanofibers were successfully fabricated by using a simple electrospinning method. The nanofibers have an average diameter of 300–500 nm and consist of many ZnCo2O4 and carbon nanoparticles. A supercapacitor fabricated using the ZnCo2O4/C nanofibers was found to exhibit a high specific capacitance of 90.0 F/g at a current density of 8.0 A/g and good rate capability under current densities in the range 0.5–8.0 A/g at a voltage of 0.4 V. It also has superior working stability with a capacitance retention of 125% after 1000 cycles in air.

Novel One-Dimensional Hollow Carbon Nanotubes/Selenium Composite for High-Performance Al-Se Batteries.

Herein, we successfully prepared one-dimensional nanowire with carbon-coated selenium (Se@CW) by using a simple wet chemical method and obtained a one-dimensional hollow Se@C nanotube (Se@CT) after the subsequent calcination treatment. We have formed a new Al-Se secondary battery by using Se@CT as the cathode and metal aluminum as the anode in the AlCl3/[EMIm]Cl electrolyte. It is believed that the oxidation intermediate of Se in Al-Se batteries may not only have Se22+, but there may be other oxidation intermediates, such as Se4+, Se2+, and Se82+. Therefore, Se@CT exhibits excellent charge-discharge performance in Al-Se batteries. Its initial discharge capacity reaches 447.2 mA h g-1 at 200 mA g-1, and the operating voltage is above 1.6 V. Its energy density approaches 708.8 W h k g-1, the capacity is still 162.9 mA h g-1 after 200 cycles at 500 mA g-1, and the corresponding capacity retention rate is up to 83.5%. In addition, its electrochemical performance is far superior to that of Se@CMK-3 in Al-Se batteries and the electrochemical properties of carbon materials, oxides, and sulfide electrode materials in some aluminum-ion batteries, which will open up a new direction for the development of new secondary aluminum-based batteries.

Microscopic Origin of the Solid Electrolyte Interphase Formation in Fire-Extinguishing Electrolyte: Formation of Pure Inorganic Layer in High Salt Concentration.

A highly salt-concentrated (HC) electrolyte based on the nonflammable solvent trimethyl-phosphate (TMP) has recently shown an attractive self-extinguishing property in addition to an excellent charge-discharge performance. However, the microscopic understanding of its solid electrolyte interphase (SEI) layer remains an open question. In this Letter, the red moon (RM) method was used to investigate the molecular mechanism of SEI layer formation depending on lithium bis(fluorosulfonyl)amide (LiFSA) salt concentration in a TMP-based electrolyte and was able to reproduce successfully the experimental observations, i.e., the "bottom-up" formation mechanism with a thinner and denser SEI layer mainly based on salt reduction in the HC electrolyte. The results showed that a pure dense inorganic layer is formed in the HC electrolyte, which should considerably improve the SEI layer stability leading to a longer lifetime in charge-discharge performance. This new microscopic finding should provide an important guide in designing an effective nonflammable electrolyte to develop advanced, safe secondary batteries.