High Charge Capacity Research Articles

Facile recycling of porous Si waste for stable Si/C anodes

As the rapid development of photovoltaic industry, vast of polycrystalline Si has been produced for photovoltaic products. Meanwhile, large amount of Si waste is generated from mechanical slicing process and retired electronic products. Reasonable recycling the Si waste can save resources and reduce environmental pollution. Herein, porous Si is prepared from Si waste by magnesium thermal reduction and then embedded in industry lignin alkali-based carbon matrix (LAC) via co-precipitation and sintering process to obtain Si/C composite anode for lithium-ion batteries. Owing to the encapsulation structure, the carbon matrix can alleviate the volumetric expansion of Si and improve electronic conductivity of composite, the obtained Si@LAC anode exhibits high charge capacity of 1017.5 mAh g−1 at 0.1 A g−1 and high capacity retention of 94.9 % at 0.5 A g−1 after 200 cycles. Furthermore, the Si@LAC composite displays superior rate performance with high capacity of 596.7 mAh g−1 at 2 A g−1 which is 61.5 % of the value at 0.2 A g−1. Such a high performance Si/C anode from facile preparation demonstrates a viable route to utilization of photovoltaic Si waste and industrial lignin.

Performances of MnO2 and SnO2 Coated MnO2 as Cathode Materials for Aqueous Rechargeable Zinc-ion Batteries

In this study, the micro-emulsion method was used to create the manganese-based cathode materials MnO2 and MnO2@SnO2. For the use as cathode materials in rechargeable zinc-ion batteries, MnO2 and SnO2 coated MnO2@SnO2 were synthesized. FT-IR, Powder X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray Spectroscopy (EDS), and UV-visible Spectroscopy were used to characterize the as-prepared materials. Electrochemical impedance spectroscopy (EIS), battery charge-discharge (BCD), and cyclic voltammetry (CV) techniques were used to investigate the electrochemical properties of the prepared cathode materials for aqueous rechargeable zinc-ion batteries (ARZIBs). The CV profiles were measured in the potential range of 2.1-1.0 V at a scan rate of 20 mV/s. A pair of redox peaks can be seen in the cycle of CV curves. Charge/discharge cycles of SnO2 coated MnO2@SnO2 electrodes are higher than those of pristine MnO2. SnO2 coated MnO2@SnO2 electrodes have better initial charge/discharge capacities than pristine MnO2 electrodes, which is a factor to take into account. In the first cycle, SnO2 coated MnO2@SnO2 electrode has a 26% higher charge capacity than the bare MnO2 electrode. The SnO2 coating on MnO2 may be the cause of the enhanced charge and discharge capabilities of MnO2@SnO2. J. of Sci. and Tech. Res. 5(1): 83-92, 2023

Mildly expanded graphite with exceptional performance from waste lithium ion batteries by space-confined intercalation of deep eutectic solvent

Reclaiming the spent graphite (SG) in the anodes of end-of-life lithium-ion batteries (LIBs) is of tremendous significance for addressing resource shortage and eco-friendliness. The impurities embedded into the graphite interlayer after multiple charge–discharge cycles hinder the free migration of lithium ions, resulting in inferior lithium storage capacity. Herein, a space-confined intercalation of deep eutectic solvent (DES) strategy is proposed, to dissolve the impurities by utilizing its great ability to form hydrogen bonds (O–H…Cl-, O–H…O and O–H…F) with PVDF binder, SEI film and the residual electrolytes within the SG, simultaneously enlarging the interlayer distance to upgrade the anode graphite. After the further pyrolysis, the as-obtained mildly expanded graphite (MEG-800) exhibited well-defined graphite microcrystalline layer structure and high graphitization degree. The moderately enlarged graphite layers provided more space for the insertion and extraction of lithium ions, endowing MEG-800 with exceptional performance in LIBs, such as extremely high charge capacity of 477.4 mAh/g at a current density of 0.1 A/g and superior reversibility and desirable cycle stability. After 100 cycles at 0.1 A/g, its capacity still retained 470.9 mAh/g with a Coulombic efficiency as high as 99.76 %. The structure-dependent lithium-ion diffusion features of MEG-800 were also examined by electrochemical kinetics analysis. This study opened up a prospective avenue for the green and efficient recycling of spent anode graphite in retired LIBs, offering a solution to the problem of shortage of battery materials and promoting sustainable development.

Highly Graphitized Coal Tar Pitch-Derived Porous Carbon as High-Performance Lithium Storage Materials.

Because of its high specific capacity and superior rate performance, porous carbon is regarded as a potential anode material for lithium-ion batteries (LIBs). However, porous carbon materials with wide pore diameter distributions suffer from low structural stability and low electrical conductivity during the application process. During this study, the calcium carbonate nanoparticle template method is used to prepare coal tar pitch-derived porous carbon (CTP-X). The coal tar pitch-derived porous carbon has a well-developed macroporous-mesoporous-microporous hierarchical porous network structure, which provides abundant active sites for Li+ storage, significantly reduces polarization and charge transfer resistance, shortens the diffusion path and promotes the rapid transport of Li+. More specifically, the CTP-2 anode shows high charge capacity (496.9 mAh g-1 at 50 mA g-1), excellent rate performance (413.6 mAh g-1 even at 500 mA g-1), and high cycling stability (capacity retention rate of about 100 % after 1,000 cycles at 2 A g-1). The clean and eco-friendly large-scale utilization of coal tar pitch will facilitate the development of high-performance anodes in the field of LIBs.

OptiGun GA04 powder gun with high charging capacity

OptiGun GA04 powder gun with high charging capacity

High-Capacity spatial confined deposition/stripping enabled by biphasic modulation strategy for highly reversible zinc anodes

The development of aqueous zinc ion batteries (AZIBs) faces two major challenges: dendrites Zn and parasitic reaction, which originates from the random zinc deposition at the anode interface and the abundant free H2O activity of the solvation structure. Here, we report a biphasic modulation strategy (anode interface construction and solvation structure regulation) to solve these two issues simultaneously. Through introducing trace dynamic molecular additives, the rampant alkaline zincate byproducts at the anode interface are in situ converted to three-dimensional (3D) interconnected zinc deposition/stripping templates, while the solvation structure is effectively tailored to inhibit the overactivity of electrolyte. In situ Raman and molecular dynamics simulations verify that the Zn2+ flux during the electrochemical cycles is regulated in an orderly manner, hydrogen evolution reactions (HER) and dendrites zinc growth are effectively prevented. Zinc metal deposition/stripping is effectively confined to the 3D host space by solvation structure modulation and templates guidance, thus optimizing the crystallographic and zinc metal utilization rate during electrochemistry cycling. Even under extreme conditions, such as a high (dis)charge capacity of 10 mAh cm−2, symmetrical cells assembled based on a biphasic modulation strategy maintain long-term stability of over 1000 h.

Chemiresistive sensor based on PMMA/rGO composite for detection ammonia

Reduced graphene oxide (rGO) has been a promising material in sensing applications. However, rGO-based sensors have very high recovery time at room temperature (RT). Therefore, various materials combination needs to explored to address this issue. We have developed chemiresistive sensor based on a composite of Poly (methyl methacrylate) (PMMA) and rGO for detection of ammonia (NH3). To prepare more oxidized graphene oxide (GO), peroxidation of graphite oxide (PGO) was used from graphite by following Improved Hummer’s Method (IHM). Due to PGO, synthesized rGO was more conductive and high charge capacity. Synthesized PMMA/rGO composite was drop cast on fabricated interdigitated copper electrodes. Various characterization tools were used for materials confirmation. The chemiresistive sensor based on PMMA/rGO exhibited very good sensing behaviour towards NH3 analytes. The range of detection was 1–10 ppm with very good reproducibility. It was far below the Occupational Safety and Health Administration Permissible Exposer Limit (OSHA PEL) of NH3. A chemiresistive sensor based on PMMA/rGO composite revealed better sensing results than a pristine rGO sensor. The response time and recovery time for rGO based sensor was 122 s and 168 s respectively at 2 ppm of NH3 whereas for PMMA/rGO based sensor it was 50 s and 75 s respectively. Moreover, the PMMA/rGO based sensor exhibited repeatability at 2 ppm for NH3 at RT. This type of PMMA/rGO sensor will be very much useful for the detection of hazardous gases in chemical laboratories and industrial areas.

Enhancing Cycle Stability via Discharge Voltage Regulation in Li–S Batteries: Impact of the Lower Cutoff Voltage on Electrochemical Stability

The lithium–sulfur (Li–S) battery emerges as a candidate for next-generation batteries owing to its superior energy density and cost-effectiveness. Despite these advantages, the longevity of Li–S batteries remains a complex challenge. The shuttle effect has been identified as a principal factor contributing to degradation, prompting extensive research aimed at mitigating its impact. Recent studies, however, have unveiled that the presence of Li2S exerts a significant influence on the kinetics and stability of the electrochemical reaction. Although lower cutoff voltage directly controls the formation of Li2S, its relationship between lower cut-off voltage and Li2S formation has not been investigated so far. In this study, we regulated the discharge voltage and revealed the relationship between lower cutoff voltage and electrochemical stability. A low lower cut-off voltage increased Li2S formation and the first discharge capacity but reduced Li2S transformation to sulfur, as confirmed by the high overpotential and low charge capacity. Furthermore, repeated cycles at a high discharge exhibited severe capacity loss and deteriorated Coulombic efficiency. By contrast, a high lower cut-off voltage cell exhibited enhanced capacity retention with a low overpotential owing to the inhibition of Li2S formation. Thus, this study provides insights into controlling Li2S formation, which is critical to stabilizing the electrochemical reaction and enhancing the cycle stability of Li–S batteries.

Melamine Polymerization Promotes Compact Phosphorus/Carbon Composite for High-Performance and Safe Lithium Storage.

Phosphorus is regarded as a promising material for high-performance lithium-ion batteries (LIBs) due to its high theoretical capacity, appropriate lithiation potential, and low lithium-ion diffusion barrier. Phosphorus/carbon composites (PC) are engineered to serve as high-capacity high-rate anodes; the interaction between phosphorus and carbon, long-term capacity retention, and safety problems are important issues that must be well addressed simultaneously. Herein, an in situ polymerization approach to fabricate a poly-melamine-hybridized (pMA) phosphorus/carbon composite (pMA-PC) is employed. The pMA hybridization enhances the density and electrical conductivity of the PC, improves the structural integrity, and facilitates stable electron transfer within the pMA-PC composite. Moreover, the pMA-PC composite exhibits efficient adsorption of lithium polysulfides, enabling stable transport of Li+ ions. Therefore, the pMA-PC anode demonstrates a high specific charging capacity of 1,381mAhg-1 at 10Ag-1, and a great capacity retention of 86.7% at 1Ag-1 over 500 cycles. The synergistic effect of phosphorus and nitrogen further confers excellent flame retardant properties to the pMA-PC anode, including self-extinguishing in 2.5s, and a much lower combustion temperature than PC. The enhanced capacity and safety performance of pMA-PC show potential in future high-capacity and high-rate LIBs.

Facile Fabrication of Large-Area CuO Flakes for Sodium-Ion Energy Storage Applications.

CuO is recognized as a promising anode material for sodium-ion batteries because of its impressive theoretical capacity of 674 mAh g-1, derived from its multiple electron transfer capabilities. However, its practical application is hindered by slow reaction kinetics and rapid capacity loss caused by side reactions during discharge/charge cycles. In this work, we introduce an innovative approach to fabricating large-area CuO and CuO@Al2O3 flakes through a combination of magnetron sputtering, thermal oxidation, and atomic layer deposition techniques. The resultant 2D CuO flakes demonstrate excellent electrochemical properties with a high initial reversible specific capacity of 487 mAh g-1 and good cycling stability, which are attributable to their unique architectures and superior structural durability. Furthermore, when these CuO flakes are coated with an ultrathin Al2O3 layer, the integration of the 2D structures with outer nanocoating leads to significantly enhanced electrochemical properties. Notably, even after 70 rate testing cycles, the CuO@Al2O3 materials maintain a high capacity of 525 mAh g-1 at a current density of 50 mA g-1. Remarkably, at a higher current density of 2000 mA g-1, these materials still achieve a capacity of 220 mAh g-1. Moreover, after 200 cycles at a current density of 200 mA g-1, a high charge capacity of 319 mAh g-1 is sustained. In addition, a full cell consisting of a CuO@Al2O3 anode and a NaNi1/3Fe1/3Mn1/3O2 cathode is investigated, showcasing remarkable cycling performance. Our findings underscore the potential of these innovative flake-like architectures as electrode materials in high-performance sodium-ion batteries, paving the way for advancements in energy storage technologies.

Increasing the capacity of pseudocapacitive WO3 auxiliary electrode for enhanced two-step decoupled acid water electrolysis

Decoupled water electrolysis has all the necessary properties to become an effective hydrogen production tool. Hydrogen evolution is decoupled from oxygen evolution using red-ox mediator electrodes in decoupled electrolysis. Therefore, oxygen and hydrogen are not produced simultaneously or in the same space. This simplifies the design of electrolysers and opens up the possibility of not using membranes and diaphragms for gas separation as conventional electrolysers do. Also, membrane-free technology improves the durability and efficiency of electrolysers. The reduction and oxidation of the red-ox mediator electrode must be reversible. Also, the electrode material should have a high charge capacity and be durable. In this work, we demonstrate WO3 as a red-ox mediator electrode in decoupled water electrolysis with acid electrolyte and investigate the effect of lyophilisation and annealing conditions on WO3 capacity. Indeed, the WO3 electrode can successfully act as a red-ox mediator through intercalation and deintercalation of H+ ions. Lyophilisation increases capacity more than two times than the air-dried sample, 495.55 and 201.41 F/g, respectively. Such high capacities as 837.43 F/g were reached when an inert annealing atmosphere was used. The electrolysis faradaic efficiency of 98–99 % was achieved in all prepared samples, with an energetical efficiency of 34–58 %.

A composite material consisting of tin nanospheres anchored on and embedded in carbon nanofibers for outstanding sodium-ion storage

Benefiting from the abundant availability of sodium resources and the relative lower cost, sodium-ion batteries (SIBs) are increasingly garnering attention. However, there is a pivotal challenge in contemporary battery research, revolves around the advancement of electrode materials that are both high-performing and abundant in nature. Sn-based materials stand out as promising anodes in SIBs owing to the high theoretical capacity (847 mA h g−1) of metallic tin. Herein, a composite of Sn nanospheres anchored on and embedded in the carbon nanofibers (Sn@CNFs) has been synthesized by electrospinning and the following annealing process. After that, the Sn@CNFs was directly used as free-standing anodes for sodium-ion batteries. Remarkably, with assistance of K+ in the electrolyte, the Sn@CNFs anode sustains a capacity of 470.3 mA h g−1 over 450 cycles with a superb Coulombic efficiency (CE) of 99.71 %. Additionally, with a high cycle retention of 99.0 %, the Sn@CNFs||NVP full-cell delivers high charge and discharge capacity of 100.7 and 99.8 mA h g−1 at 0.1C after 50 cycles.

Zinc ion storage abilities of Mo3WOx nano-ceramic under extreme-cold environments

It is imperative to develop new electrode materials for aqueous multivalent metal ion batteries with electrochemistry abilities at extreme-low temperatures due to the possible extreme-cold operating conditions of batteries in the present or the future. Herein, as a proof-of-concept experiment, a new orthorhombic molybdenum-tungsten oxide (Mo3WOx) is synthesized by a wet-chemical method and tested as anode material for aqueous zinc ion batteries at extreme-cold temperatures (−40, −60 and −75 °C) for the first time. Two anti-freezing electrolytes are selected to examine the related half-cell performances, and 7.5 m ZnCl2 aqueous solution is more suitable for Mo3WOx half-cells than 2 m Zn(BF4)2 aqueous solution. At −40 °C, Mo3WOx exhibits reversible charge capacity of 104.1 mAh g−1 at 100 mA g−1 and the charge capacity can still maintain 82.3 mAh g−1 after 100 cycles; and under further test at 5000 mA g−1, Mo3WOx shows a high initial charge capacity of 42.5 mAh g−1 together with a capacity retention ratio of 81.6 % after 10,000 cycles. It is worth highlighting that the high capacities of Mo3WOx delivered at −40 °C are even comparable with the capacities of some “new-type” anode materials for aqueous zinc ion batteries exhibited at ambient temperature. At colder temperatures of −60 and −75 °C, the as-prepared compound still owns certain zinc ion storage abilities, especially high discharge/charge capacities of 48.9/48.7 mAh g−1 can be still achieved in the 100th cycle at −75 °C (100 mA g−1). Furthermore, a full-cell with operational capability at −40 °C is also built here, and it can exhibit discharge capacity of 66.1 mAh g−1 (coulombic efficiency of 99.7 %) in the 3rd cycle and discharge capacity of 48.2 mAh g−1 (coulombic efficiency of 99.7 %) in the 50th cycle.

A fault diagnosis method of battery internal short circuit based on multi-feature recognition

The internal short circuit (ISC) fault has been considered as one of the most serious problems, which may pose a threat to the operation safety of the battery system. To solve this problem, this paper proposes an ISC fault diagnosis method based on multi-feature recognition to distinguish aging and ISC fault. The ISC equivalent circuit model is established first. In addition, three characteristic parameters, including the slope of the “rebound” voltage curve, the “valley” ordinate in the differential voltage (DV) curve, and the electric quantity, namely high segment charging capacity (HSCC) between the valley point of the DV curve and the end of charging position, are extracted to distinguish the ISC battery from aging battery. The results show that the proposed method can effectively distinguish between ISC batteries, aging batteries, and normal batteries. Moreover, the ISC resistance is able to be estimated accurately, with an error of less than 5.44%.

Crystallization-induced formation of two-dimensional carbon nanosheets derived from sodium lignosulfonate for fast lithium storage

Sodium lignosulfonate, an abundant natural resource, is regarded as an ideal precursor for the synthesis of hard carbon. The development of high-performance, low-cost and sustainable anode materials is a significant challenge facing lithium-ion batteries (LIBs). The modulation of morphology and defect structure during thermal transformation is crucial to improve Li+ storage behavior. Synthesized using sodium lignosulfonate as a precursor, two-dimensional carbon nanosheets with a high density of defects were produced. The synergistic influence of ice templates and KCl was leveraged, where the ice prevented clumping of potassium chloride during drying, and the latter served as a skeletal support during pyrolysis. This resulted in the formation of an interconnected two-dimensional nanosheet structure through the combined action of both templates. The optimized sample has a charging capacity of 712.4 mA h g−1 at 0.1 A g−1, which is contributed by the slope region. After 200 cycles at 0.2 A g−1, the specific charge capacity remains 514.4 mA h g−1, and a high specific charge capacity of 333.8 mA h g−1 after 800 cycles at 2 A g−1. The proposed investigation offers a promising approach for developing high-performance, low-cost carbon-based anode materials that could be used in advanced lithium-ion batteries.

Design of cobalt phosphate/nickel phosphate films with improved electrochromic performance

The composite metal phosphate film (CoHPO4/NiHPO4 film) shows excellent electrochromic properties including good optical modulation, fast switching time, high charge capacity, high coloration efficiency and outstanding cycling stability.

Solution Processable Polyaniline with High Electrochemical Charge Capacity

Polyaniline (PANI) is a charged polymer well-known for its high charge storage capacity and moderate electrical conductivity. PANI is often prepared by chemical or electro-polymerization, however, these polymerization methods limit options for substrate material, electrode/device geometry, and polymer morphology. To address these limitations, it is attractive to form PANI films by solution-casting. In this study, we examine the electrochemical properties of solution-cast PANI films formed from a commercially available PANI suspension containing excess dinonylnaphthalenesulfonic acid (DNNSA). Films prepared by solution casting of PANI-DNNSA have been previously characterized in terms of conductivity, morphology, and optical properties, however the electrochemical behavior of these films has been largely unexplored. Here, we present an electrochemical analysis of these solution-cast PANI films using quartz crystal microbalance, electrochemical impedance spectroscopy, and cyclic voltammetry. As cast, we find that the polymer exhibits limited electrochemical activity, but that postprocessing the material with electrolyte and crosslinking solutions increases the charge capacity up to 95 mAh/g – 86% of the charge capacity typically reported for electrodeposited PANI films. Ion-exchange processes, electrochemical capacitance, and energy storage capabilities of the chemically treated solution-cast films are assessed and compared to those of electro-deposited and chemically oxidized PANI. We demonstrate redox-active PANI films on both (a) conductive and insulating, and (b) planar and porous substrates. Finally, symmetric faradaic supercapacitor devices were constructed using spin-coated PANI electrodes in aqueous electrolyte, and the stability of these devices was examined by repeat galvanostatic charging/discharging at low current, achieving up to 88% capacity retention after 500 charge-discharge cycles.

Passivated Bi2Se3 electrode in Na2CO3 solution to improve anode efficiency in aqueous Li-ion batteries

Efficient anode materials are crucial for the success of aqueous rechargeable lithium-ion batteries (ALIBs) since many materials degrade significantly during electrochemical reactions. In this study, the modification of Bi2Se3 with Na2CO3 was explored to enhance the charge–discharge characteristics of the anode. The passivated Bi2Se3 electrode exhibited improved electrochemical performance, maintaining high charge and discharge capacities of 816 mAh·g−1 after the 5th cycle and 570 mAh·g−1 after the 100th cycle with stable Coulombic efficiency of 98.0 ± 1.2 %. Charge-discharge profiles and cyclic voltammetry revealed the lithium intercalation and deintercalation, while impedance spectroscopy indicated changes in the electrode structure during cycling. These findings highlight the potential of using Bi2Se3 electrodes with a pre-formed surface film to enhance the stability and performance of ALIBs.

Synthesis of Graphitic Carbon Coated ZnPS3 and its Superior Electrochemical Properties for Lithium and Sodium Ion Storage.

Graphitic carbon-coated ZnPS3 is prepared via direct phosphosulfurization and high energy mechanical milling (HEMM) with multiwall carbon nanotubes (MWCNTs) and first introduced as an anode for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). The HEMM process with MWCNTs reduces the particle size of as-synthesized ZnPS3 bulk to 100-500nm and yields the ≈5nm thick graphitic carbon coated ZnPS3 nanoparticles, which are the nanocomposites of 5nm sized nanocrystallites embedded in the amorphous matrix. The ZnPS3 electrode undergoes the combined conversion and alloying reactions with Li and Na ions and exhibits high initial discharge and charge capacities in both LIBs and SIBs. The graphitic carbon-coated ZnPS3 electrode exhibits excellent high-rate capability and long-term cyclability. The superior electrochemical properties can be attributed to high electrical conductivity, high Li ion mobility, and high reversibility and structural stability derived from the graphitic carbon-coated nanoparticles. This study demonstrates that the novel graphitic carbon-coated ZnPS3 is a promising anode material for both LIBs and SIBs and the graphitic carbon coating methodology by HEMM is expected to apply to the various metal oxides, sulfides, and phosphides.

Cyanobacteria as an eco-friendly bioresource for EPS production with crack healing capacity in concrete

Cyanobacteria, alike microalgae, are photosynthetic microorganisms found in different environmental conditions. These photosynthetic bacteria are also considered promising solutions for cracking problem in concretes. These photosynthetic organisms precipitate CaCO3 crystals in concrete microcracks and pores, thus sealing the cracks and increasing the strength gain of the concrete blocks. Cyanobacteria Lyngbya sp., Phormidium sp., and microalgae Chlorella vulgaris were studied initially. Lyngbya sp., Phormidium sp., and Chlorella vulgaris have the additional property of secreting the exopolysaccharide (EPS). EPSs are an important class of biopolymers with great ecological importance. Because of their high charge density and capacity to act as mineralization nucleation sites, cyanobacterial exopolysaccharides are currently receiving more attention. Using the three strains stated above, this study investigates the impact of physiochemical factors on biomass concentration and exopolysaccharide synthesis and creates mathematical models. Using Central Composite Design (CCD), it is possible to study the interactions between the many parameters, including nitrate concentration, starting media pH, light intensity, and temperature. The biochemical characteristics of the leftover biomass are assessed after exopolysaccharide extraction, and because of its high carbohydrate and fat content, it can be used to produce biofuel. The study of checking the microbial crack healing capacity and strength gain of the concrete using these three cyanobacterial strains is being studied. Based on the outcome, the best species was chosen. Further microstructural analyses, such as X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to support the calcium carbonate precipitation.