Search Results (49)

Developing cost-effective yet high-performance hard carbon anodes is critical for advancing the commercialization of sodium-ion batteries (SIBs), as they offer a balance of low cost, high capacity, and compatibility with Na⁺ storage mechanisms. Herein, waste towels, an abundant, low-cost precursor with a high carbon yield (>49%), were utilized to synthesize hard carbons via a two-step process: pre-oxidation at 250 °C to stabilize the fibrous structure, followed by carbonization at 1100 °C (THC-1100), 1300 °C (THC-1300), or 1500 °C (THC-1500). Electrochemical evaluations revealed that THC-1300, carbonized at an intermediate temperature, exhibited superior Na⁺ storage performance compared to its counterparts: it delivered a high reversible specific capacity of ~320 mAh/g at 1.0 C (1 C = 320 mA/g), with 78% capacity retention after 200 cycles, demonstrating excellent long-term cyclic stability. Its rate capability was equally impressive, achieving specific capacities of 341.5, 331.2, 302.0 and 234.8 mAh/g at 0.2, 0.5, 2.0 and 5.0 C, respectively, indicating efficient Na⁺ diffusion even at high current densities. Notably, THC-1300 also showed an improved initial Coulombic efficiency (ICE) of 75.4%, reflecting reduced irreversible Na⁺ consumption during the first cycle. These enhancements are attributed to the synergistic effects of THC-1300’s optimized structural and textural properties: a balanced interlayer spacing (d₍₀₀₂₎ = 0.387 nm) that facilitates rapid Na⁺ intercalation, a low BET surface area (1.62 m²/g) helps to minimize electrolyte side reactions. The combined advantages of high specific capacity, improved ICE, and remarkable cycling stability position this waste-towel-derived hard carbon as a highly viable and sustainable candidate for anode materials in next-generation SIBs, addressing both performance and cost requirements for large-scale energy storage applications. Full article

Impressed current cathodic protection (ICCP) systems can experience acidification, which deteriorates the interface between the anode and the anode backfill mortar. This deterioration may necessitate premature intervention to remove and reinstate the backfill and, in some cases, replace the anode. If left unaddressed, acidification ultimately leads to debonding between the anode and the backfill mortar, resulting in the failure of the ICCP system. This paper presents the development of a specialised acid-resistant hybrid mortar designed for ICCP systems used to protect reinforced concrete bridges in marine environments. It also investigates the effects of acidification on the physical and mechanical properties of the proposed anode backfill mortars. Additionally, the study characterises acidification products from both field-extracted ICCP systems and laboratory-based accelerated testing, providing deeper insights into the acidification mechanisms. Novel mortar samples were subjected to varying concentrations of hydrochloric acid (HCl) under accelerated testing conditions. The incorporation of supplementary cementitious materials (SCMs), calcium sulfoaluminate (CSA) cement and zeolite significantly enhanced the strength and durability of the backfill mortars in acidic environments, while maintaining compliance with the electrical resistivity requirements (20–100 kΩ·cm) for ICCP systems. The lowest compressive strength loss observed in the developed hybrid mortar was 54% after 28 days of immersion in 5% HCl and 83% in 15% HCl. Microstructural analyses revealed that gypsum formation and chloride–sulphate competitive binding interactions are key mechanisms contributing to the improved acid resistance, particularly in CSA cement-containing formulations. Full article

The search for high-capacity, stable anode materials is crucial for advancing lithium-ion battery (LIB) technology. Although carbon nanotubes (CNTs) are known for their excellent electrical conductivity and mechanical strength, their practical capacity is still limited. This study presents an advanced anode design by molecular functionalizing both single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs) with tetrabromocobalt phthalocyanine (CoPc), resulting in CoPc/SWCNT and CoPc/MWCNT hybrid materials. Metal phthalocyanines (MPcs) are recognized for their tunable and redox-active properties. In CoPc, the redox-active metal centers and π-conjugated structure are uniformly attached to the CNT surface through strong π-π interactions. This synergistic combination significantly boosts the lithium-ion (Li-ion) storage capacity by offering numerous coordination sites for Li-ions and enhancing charge transfer kinetics. Electrochemical analysis shows that the CoPc-SWCNT active anode electrode material shows an impressive reversible capacity of 1216 mAh g⁻¹ after 100 cycles at a current density of 0.1 A g⁻¹, substantially surpassing the capacities of pristine CoPc (327 mAh g⁻¹) and a CoPc/MWCNT hybrid (488 mAh g⁻¹). Furthermore, the CoPc/SWCNT anode exhibited exceptional rate capability and outstanding long-term cyclability. These results underscore the effectiveness of non-covalent functionalization with SWCNTs in enhancing the electrical conductivity, structural stability, and active site utilization of CoPc, positioning CoPc/SWCNT hybrids as a highly promising anode material for high-performance Li-ion storage. Full article

Impressed current cathodic protection (ICCP) is one of the most effective techniques in preventing steel corrosion in concrete structures. Based on the exceptional electrical conductivity and mechanical properties of carbon fiber reinforced polymers (CFRP), a novel structural system employing ICCP is proposed in this paper, in which CFRP strips are used as both concrete stirrups and as an auxiliary anode for cathodic protection. To further verify the dual functions of CFRP strips for this new system, the electrochemical and mechanical behaviors of the CFRP strip anode are investigated experimentally in this study through the anodic polarization test, electrochemical impedance spectroscopy test, uniaxial tensile test, and interfacial acidification test. The effects of concrete type and anode current density on the properties of CFRP strip anodes are identified. The results show that the CFRP strip anode possesses satisfactory electrical conductivity and relatively low output resistance, and the ultimate strength of the CFRP strip after polarization is reduced as the current density increases due to the gradual degradation of the CFRP anode. The mechanical properties of CFRP strips in Engineered Cementitious Cement (ECC) concrete and geopolymer concrete outperform those of ordinary concrete, and the degradation rate of CFRP strips subjected to anodic polarization in ECC concrete is lower than that of geopolymer concrete. The cathodic protection mechanism of CFRP strips as an anode is further revealed via numerical analysis. In addition, the prediction model of the service life is constructed for the proposed novel concrete structural system. The predicted service life of the system decreases as the reinforcement ratio increases, and it increases as the stirrup ratio increases. The predicted service life of the ICCP system in ECC concrete is significantly longer than that in geopolymer concrete and ordinary concrete. Full article

In the context of infrastructure modernization, enhancing the durability of reinforced concrete (RC) structures is crucial for achieving sustainable and resilient development. Impressed current cathodic protection (ICCP) is a popular technique to improve corrosion resistance of RC structures exposed to chloride-rich environments but may also induce localized acidification in the external anode mortar due to continuous OH⁻ consumption and H⁺ generation. This phenomenon leads to the dissolution of calcium hydroxide and acidification erosion damage on the anode metal and mortar, undermining the long-term performance of the protection system. This study uses modified aggregates that are incorporated with Ca(OH)₂ to improve the corrosion resistance of anode metal and mortar. Results from electrochemical measurements, pH monitoring, and XRD analysis show that the Ca(OH)₂-loaded aggregates extended the stable alkaline buffer time of simulated pore solution during ICCP by 1.5 to 2 times longer and exhibited good resistance to the mortar acidification. These findings offer a promising pathway for safeguarding RC structures and advancing infrastructure modernization by integrating protective functionalities at the material level. Full article

Lithium (Li) metal’s exceptional low electrode potential and high specific capacity for next-gen energy storage devices make it a top contender. However, the unregulated and unpredictable proliferation of Li dendrites and the instability of interfaces during repeated Li plating and stripping cycles pose significant challenges to the widespread commercialization of Li metal anodes. We introduce the creation of a hydrogen bond network solid electrolyte interphase (SEI) film that integrates zwitterionic groups, designed to facilitate the stability and longevity of lithium metal batteries (LMBs). Here, we design a PVA/P(SBMA-MBA) hydrogen bond network film (PSM) as an artificial SEI, integrating zwitterions and polyvinyl alcohol (PVA) to synergistically regulate Li⁺ flux. The distinctive zwitterionic effect in the network amplifies the SEI film’s ionic conductivity to 1.14 × 10⁻⁴ S cm⁻¹ and attains an impressive Li⁺ ion transfer number of 0.84. In situ Raman spectroscopy reveals dynamic hydrogen bond reconfiguration under strain, endowing the SEI with self-adaptive mechanical robustness. These properties facilitate a homogeneous Li flux and exceptionally suppress dendritic growth. The advanced Li metal anode may endure over 1200 h at 1 mA cm⁻² current density and 1 mAh cm⁻² area capacity in a Li|Li symmetric battery. And in full cells paired with LiFePO₄ cathodes, 93.8% capacity retention is reached after 300 cycles at 1C. Consequently, this work provides a universal strategy for designing dynamic interphases through molecular dipole engineering, paving the way for safe and durable lithium metal batteries. Full article

Microbiologically influenced corrosion (MIC) is one of the key causes of material failure in marine engineering, and sulfate-reducing bacteria (SRB) and iron-oxidizing bacteria (IOB) are typical representatives of anaerobic and aerobic microorganisms, respectively. These microorganisms are widely present in marine environments and can form synergistic communities on the surface of metal materials, posing a corrosion threat to them. At the same time, the presence of mixed bacteria may have an effect on cathodic protection, so this study investigates the growth metabolism of mixed SRB and IOB under different cathodic protection potentials in an impressed current cathodic protection (ICCP) system in a marine environment containing SRB and IOB. It also examines the attachment of these microorganisms to the anode and cathode, and the impact on cathodic protection efficiency. The results indicate that in a marine environment containing IOB and SRB, the cathodic protection efficiency of the ICCP system increases with the negative shift of the protection potential. A more positive cathodic protection potential promotes the adhesion of mixed bacteria on the electrode surface and the formation of a biofilm, which reduces cathodic protection efficiency. In contrast, at a cathodic protection potential of −1.05 V (SCE), bacterial growth is inhibited, and a dense crystalline corrosion film primarily composed of Fe₂O₃ and Fe(OH)₃ forms on the cathode surface. This film effectively protects the cathodic metal, significantly mitigating MIC. Full article

Niobium pentoxide (Nb₂O₅) is a promising anode candidate for lithium-ion batteries due to its high theoretical capacity, excellent rate capability, and safe working potential. However, its inherent low conductivity limits its practical application in fast-charging scenarios. In this work, we develop an ultrathin carbon-coated two-dimensional T-Nb₂O₅ nanosheet composite (T-Nb₂O₅@UTC) through a facile solvothermal reaction and subsequent CVD acetylene decomposition. This unique design integrates a two-dimensional nanosheet structure with an ultrathin carbon layer, significantly enhancing electronic conductivity, reducing ion diffusion pathways, and preserving structural integrity during cycling. The T-Nb₂O₅@UTC electrode demonstrates an impressive specific capacity of 214.7 mAh g⁻¹ at a current density of 0.1 A g⁻¹, maintaining 117.9 mAh g⁻¹ at 5 A g⁻¹, much outperforming the bare T-Nb₂O₅ (179.6 mAh g⁻¹ at 0.1 A g⁻¹ and 62.9 mAh g⁻¹ at 5 A g⁻¹). It exhibits outstanding cyclic stability, retaining a capacity of 87.9% after 200 cycles at 0.1 A g⁻¹ and 83.7% after 1000 cycles at 1 A g⁻¹. In a full-cell configuration, the assembled T-Nb₂O₅@UTC||LiFePO₄ battery exhibits a desirable specific capacity of 186.2 mAh g⁻¹ at 0.1 A g⁻¹ and only a 1.5% capacity decay after 120 cycles. This work underscores a nanostructure engineering strategy for enhancing the electrochemical performance of Nb₂O₅-based anodes toward high-energy-density and fast-charging applications. Full article

Iron phosphide (FeP) represents a promising anode material for sodium-ion batteries, attributed to its significant theoretical capacity, moderate operating potential, and natural abundance. However, due to the low conductivity and significant volume expansion of FeP electrodes, their specific capacity and cycle life decrease rapidly during charging and discharging. In this study, we synthesized FeP nanoparticles supported on a three-dimensional porous carbon framework composite (FeP@PCF) using a straightforward colloidal blow molding method, employing iron nitrate nonahydrate and polyvinylpyrrolidone as raw materials. The nanoscale size of the FeP particles, along with the abundant mesopores and high specific surface area of the 3D porous carbon framework, contribute to the impressive sodium storage performance of FeP@PCF. It is revealed that FeP@PCF achieves a remarkable capacity of 196.6 mA h g⁻¹ at a current density of 1.0 A g⁻¹. Furthermore, after 800 cycles at this current density, it retains a capacity of 172.4 mA h g⁻¹, demonstrating excellent cycling performance. Kinetic and dynamic studies indicate that this exceptional performance is largely attributed to the well-designed FeP@PCF, which exhibits a high capacitive contribution of 88.3% at a scan rate of 1 mV s⁻¹. Full article

Lithium-ion batteries are a promising technology to promote the phase-out of fossil fuel vehicles. Increasing efforts are focused on improving their energy density and safety by replacing current materials with more efficient and safer alternatives. In this context, binary composites of organic ionic plastic crystals (OIPCs) and lithium salts show promise due to their impressive mechanical properties and ionic conductivity. Taking advantage of this, the present paper substitutes the commercial non-electrochemically active binder with an OIPC component, N-ethyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide ([C₂mpyr][FSI]), in combination with LiFSI. Slurry-formulation experiments revealed that varying the new binder’s composition allows the production of diverse LiFePO₄ (LFP) cathodes via the conventional fabrication process. Large amounts of OIPC−lithium salt mixtures in the composition yielded thick electrodes with expected nominal areal capacities of up to 3.74 mAh/cm², where the balanced composition with a reduced Li⁺ concentration can demonstrate >1.5 mAh/cm² at 0.1C. Lowering the amount of these ion-conductive binders enabled LFP cathodes to perform effectively under fast cycling conditions at a C-rate as high as 2C. Preliminary battery tests with a limited Li⁺ source demonstrated the feasibility of full-cell operation without using the lithium-metal anode. This work paves the way for developing advanced rechargeable batteries using OIPC-based ion-conductive binders for a wide range of applications. Full article

Cobalt (II, III) oxide (Co₃O₄) has recently gained attention as an alternative anode material to commercial graphite in lithium-ion batteries (LIBs) due to its superior safety and large theoretical capacity of about 890 mAh g⁻¹. However, its practical application is limited by poor electrical conductivity and rapid capacity degradation because of significant volume increases and structural strain during repeated lithiation/delithiation cycles. To address these issues, this work presents a novel approach to synthesizing carbon-composited Co₃O₄ microspheres (Co₃O₄@C), using abietic acid (AA) as a carbon source to increase conductivity and structural stability. The resulting Co₃O₄@C anodes show an impressive discharge capacity of 1557.4 mAh g⁻¹ after 200 cycling processes at a current density of 0.1 C, representing a significant improvement over bare Co₃O₄. This study demonstrates the potential of carbon-compositing as a strategy to mitigate the limitations of Co₃O₄ and extend its cyclability, making it a viable candidate for next-generation LIB anodes. Full article

Debonding of the primary anode caused by anodic acidification is one of the major failure modes of the impressed current cathodic protection (ICCP) system in reinforced concrete structures. This study used 3D micro X-ray computed tomography (μ-XCT) to monitor the in situ evolution of the anodic acidification-affected zone. Samples were scanned after 0 to 40 days of the accelerated anodic acidification test. The anodic acidification-affected zone was identified in μ-XCT images using the gray level segmentation method. The total volume of this zone was measured using the 3D reconstruction method. It was found that detailed 3D information can be extracted using the 3D reconstruction method. The spatial heterogeneity was analyzed using this reconstructed volume information. The Faraday efficiency was calculated and found to increase after 20 days of operation. It was also found that the affected zone was proportional to the input electrical energy. The proposed model is useful for estimating the durability of an ICCP system. Full article

This study compared the advantages and disadvantages of various corrosion protection methods for steel rebars and clarified the advantages of the cathodic protection (CP) method in the application of corrosion protection in marine structures. The advantages and disadvantages of sacrificial anodes and impressed current technology for the CP of steel rebars in marine structures were further discussed in detail, and the feasibility of CP applications in practical engineering was evaluated. Full article

In this study, we have synthesized a nanostructured core–shell framework of carbon-coated copper sulfide (C@CuS) through a one-step precipitation technique. The carbon sphere template facilitated the nucleation of CuS nanostructures. The synthesized nanocomposites have demonstrated remarkable lithium-ion storage capabilities when utilized as an anode in lithium-ion batteries. Notably, they exhibit an impressive rate capability of 314 mAh g⁻¹ at a high current density of 5000 mA g⁻¹, along with excellent long-term cycle stability, maintaining 463 mAh g⁻¹ at 1000 mA g⁻¹ after 800 cycles. This superior performance is due to the core–shell architecture of the composite, where the carbon core enhances the conductivity of CuS nanoparticles and mitigates volume expansion, thus preventing capacity loss. Our study not only elucidates the significance of carbon in the construction of nano-heterojunctions or composite electrodes but also presents a practical approach to significantly boost the electrochemical performance of CuS and other metal sulfides. Full article

Steel monopile support structures for offshore wind turbines require protection from corrosion and consideration with respect to biofouling on their external and internal surfaces. Cathodic protection (CP) works effectively to protect the external surfaces of monopiles, but internally, byproducts from aluminum sacrificial anode CP (SACP) and impressed current CP (ICCP) induce acidification that accelerates steel corrosion. Through an 8-week sea water deployment of four steel pipes, this project investigated the effect of perforations on internal CP systems. Additionally, marine growth on the internal and external surfaces of the pipes was assessed. SACP and ICCP systems inside perforated pipes performed similarly to external systems at a lower current demand relative to internal systems in sealed pipes. The organisms that grew inside of the perforated SACP and ICCP pipes were similar, suggesting that the CP systems did not affect organism recruitment. The results of this study demonstrate the potential benefits of designing perforated monopiles to enable corrosion control while providing an artificial reef structure for marine organisms to develop healthy ecosystems. Full article