Journal of Solid State Electrochemistry最新文献

This study demonstrates a synergistic dual-doping strategy employing Ca²⁺ and Br⁻ to optimize the electrochemical performance of LiNi_0.8Co_0.1Mn_0.1O₂ (NCM) cathodes. Experimental and theoretical analyses reveal that Ca²⁺ doping stabilizes the lattice structure via a "pillar effect" in the Li layer and strengthens Ca-O bonding energy, achieving an exceptional capacity retention of 90.06% of Ca-NCM after 100 cycles at 1 C. In contrast, Br⁻ doping facilitates Li⁺ extraction/insertion through weakened Li-Br bonds, delivering a high discharge capacity of 244.8 mAh·g⁻¹ of Br-NCM at 0.1 C, yet suffers from poor cyclability (67.12% retention) due to insufficient relative electron number near the Fermi level (1.4998). Remarkably, the Ca²⁺-Br⁻ dual-doped NCM integrates these advantages, synergistically enhancing electronic and ionic conductivity. Density functional theory (DFT) calculations confirm a narrowed bandgap (2.2614 → 1.7792 eV) and doubled relative electron number (0.6188 → 2.0443) near the Fermi level, significantly improving electronic conductivity. This mitigates polarization (0.187 → 0.103 V) and reduces interfacial resistance, enabling a capacity retention of 87.79% of Ca-Br-NCM at 1 C. Simultaneously, Li⁺ migration barriers decrease by 32% (0.967 → 0.658 eV) due to expanded Li layer spacing, boosting rate capability (166.3 mAh·g⁻¹ at 5 C). The dual doping thus balances high capacity (234.1 mAh·g⁻¹), cyclability (87.79%), and rate performance (41.2% improvement at 5 C vs. pristine NCM), outperforming single-doped counterparts. These findings provide atomic-scale insights into the coupling mechanism of anion-cation dual doping, advancing the design of high-performance layered oxide cathodes for next-generation lithium-ion batteries.

Accurate detection of dopamine (DA) is vital for the diagnosis and monitoring of neurological disorders, but developing electrochemical sensors that combine high sensitivity, selectivity, and scalability remains a persistent challenge. We report a molten salt–assisted synthesis strategy for engineering nickel–iron oxide (NiFeO_x) nanostructures tailored for non-enzymatic dopamine detection. By employing KNO₃ and KOH as molten salt fluxes, we successfully transformed hydrothermally prepared Ni_0.75Fe_0.25OOH precursors into hierarchical nanoflowers and nanosheets, respectively. Structural and surface characterizations confirmed that molten salt treatment significantly enhanced porosity, electroactive surface area, and charge transfer characteristics. Electrochemical measurements revealed that the KNO₃-derived NiFeO_x nanoflowers delivered excellent sensing performance, achieving a sensitivity of 1.72 μA cm⁻² μM⁻¹, a detection limit of 1.4 μM, and a quantification limit of 5.68 μM. The sensor also demonstrated high selectivity against common interferents (ascorbic acid, glucose, uric acid) and reliable performance in real sample analysis with 97.6–103.5% recovery and 1.7–2.5% RSD. These results demonstrate the effectiveness of molten salt synthesis as a scalable route for tuning NiFeO_x nanoarchitectures and optimizing their electrochemical functionality.

Hard carbon (HC) has broad prospects as anode material for sodium-ion batteries (SIBs). However, the low initial coulombic efficiency (ICE) and poor cycle stability limit its further development, due to the formation of unstable solid electrolyte interphase (SEI) layer during the charge and discharge process. Herein, a simple coating strategy was used to modify sucrose-based hard carbon spheres, which effectively improved the ICE and cycle stability of HC. Sucrose is used as the carbon source, and low-cost and low-toxicity polyvinyl pyrrolidone (PVP) is utilized as the raw material for the coating layer. The PVP coating layer can effectively reduce the contact between HC spheres and the electrolyte, thereby inhibiting the decomposition of the electrolyte and the formation of the SEI layer, and thus obtaining enhanced ICE. In addition, the N element in the coating layer can improve the conductivity of the HC material, thereby improving the electrochemical performance. Specifically, the optimal HC@NC-7 anode delivers a reversible capacity of 297.5 mAh g⁻¹, an ICE of 67.8%, and excellent cycling stability (88.8% capacity retention after 200 cycles). Therefore, this work provides a simple and low-cost strategy to develop high-performance hard carbon anode materials for SIBs.

Corrosion, fouling, and wear problems seriously endanger ocean engineering equipment. Traditional coatings were insufficient to solve the aforementioned problems simultaneously. Here, we develop a Co-CeO₂@MoS₂ composite coating with improved resistance to fouling, wear, and corrosion resistance by a simple electrodeposition technique. Morphological, structural, and performance variations of Co-CeO₂@MoS₂ composite coatings with increasing concentrations of CeO₂@MoS₂ are systematically investigated. Results show that the synergistic effect of self-lubricating soft MoS₂ sheets and high load-bearing capacity of hard CeO₂ particles provides the composite coating with remarkable friction reduction and wear resistance. In addition, the physical labyrinth effect of MoS₂ and the chemical inhibition effect of CeO₂ endows the composite coating with excellent anti-corrosion properties. Moreover, CeO₂@MoS₂ exhibits antibacterial adhesion behavior and provides the composite coating with excellent antifouling performance. The Co-CeO₂@MoS₂ composite coating deposited with 1.0 g/L CeO₂@MoS₂ exhibits the best resistance to wear, corrosion, and fouling. This work provides a simple strategy for constructing coatings with remarkably comprehensive performance for marine applications.

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Designing novel conducting polymers as energy storage materials is a viable route to construct energy storage devices with high performance. Here, 1,10-phenanthroline and its derivatives (5-amino-1,10-phenanthroline and 1,10-phenanthroline-5,6-dione) are electropolymerized in aqueous electrolytes under anodic potentials. All polymers exhibit layered morphology, but with different contents of O and N in the structure. Three aqueous electrolytes, 1 M H₂SO₄, 1 M ZnSO₄, and 1 M Na₂SO₄, are chosen to investigate the charge storage performance of these polymers. The poly(1,10-phenanthroline-5,6-dione) (PPD/CP) exhibits the best performance in all three electrolytes, with 146.3 mAh g⁻¹ at 1 A g⁻¹ in 1 M H₂SO₄. The high specific capacity arises from the plentiful redox-active sites available. The cycling stability of these polymers is systematically evaluated. All polymers exhibit battery-type behavior in aqueous electrolytes. The charge storage mechanism of PPD/CP is investigated, revealing that the process involves redox reactions of amino/imino and hydroxyl/carbonyl functional groups, accompanied by the reversible insertion and extraction of cations. A two-electrode device using PPD/CP, a zinc foil, and 1 M ZnSO₄ is assembled and exhibits a specific capacity of 154.2 mAh g⁻¹ at 1 A g⁻¹. The device achieves an energy density of 71.25 Wh kg⁻¹ at a power density of 450 W kg⁻¹. A capacity retention of 81.9% is maintained after 2000 cycles at a current density of 5 A g⁻¹.

Direct methanol fuel cell (DMFC) is a potential new energy option with high energy density and storage convenience. In this work, a novel platinum-coated titanium fiber felt (Pt/TFF) cathode current collector is designed, and its performance enhancement mechanism is investigated through a combination of theoretical analysis and experimental tests. It is shown that the Pt coating significantly increased the catalytic active area while enhancing the current collector’s hydrophobicity and effectively reducing water retention. Electrochemical experiments showed that the structure increased the optimal methanol concentration of DMFC from 1 to 2 mol/L, the maximum power density from 38.84 to 53.96 mW/cm², and the constant current discharge time from 80 to 107 min. Electrochemical impedance spectroscopy (EIS) analysis further confirmed that the structure reduced ohmic impedance, charge transfer impedance, and mass transfer impedance and significantly improved the reaction efficiency and stability of the cell.

Polyolefin separators are widely used in commercial lithium-ion batteries (LIBs), but their inherent limitations, such as poor thermal stability and low electrolyte wettability, restrict the further improvement of LIB performance. This paper presents a novel process for recovering and preparing submicron level AlOOH (boehmite) from the waste liquid of aluminum electrolytic capacitors. In addition, AlOOH/PVP@PP composite separators were prepared by utilizing polyvinylpyrrolidone (PVP), which has high thermal stability, as a binder, which significantly improves the thermal stability and electrochemical performance of lithium-ion batteries. The results of the study showed that the incorporation of polyvinylpyrrolidone (PVP) binder and AlOOH greatly improved the thermal stability of polypropylene (PP) separators. The thermal shrinkage of the AlOOH/PVP@PP separator at 180 °C was significantly reduced from 10.1% to 1.5% compared to the AlOOH/PVDF@PP separator fabricated with the conventional binder, while the structure of the AlOOH coating remained unchanged without significant changes. In addition, the voids between the AlOOH particles in the coating help to improve the containment of the electrolyte, which significantly improves the wettability of the separator. More importantly, the strong polarity of the PVP binder enhances the wettability of the separator to the electrolyte, improves the lithium-ion migration efficiency in the AlOOH/PVP@PP separator, and raises the ion transfer number from 0.447 to 0.661, thereby improving the electrochemical performance of the battery.

Graphical Abstract

This study leveraged the waste liquid from aluminum electrolytic capacitors to synthesize submicron-sized boehmite (AlOOH). It further employed PVP-a thermally stable binder with strong adhesion to both PP and AlOOH-to fabricate the AlOOH/PVP@PP composite separator. This innovative composite separator substantially enhanced the safety and electrochemical performance of the battery.

The electrochemical behavior of rutin on cerium oxide/cobalt phthalocyanine-multiwalled carbon nanotube-modified glassy carbon electrode (CeO₂/MWCNT-CoPc/GCE) film was examined using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and amperometry in a Britton-Robinson buffer at pH 3.0. The physical and chemical characterization of the modified electrode was carried out with scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and electrochemical impedance spectroscopy (EIS). The DPV results showed that the developed CeO₂/MWCNT-CoPc/GCE demonstrated a linear concentration range between 1.0 × 10⁻⁷ mol L⁻¹ and 2.8 × 10⁻⁵ mol L⁻¹ with a limit of detection of 0.12 μ mol L⁻¹ (S/N = 3). In addition, amperometric measurements had higher sensitivity and revealed two distinct ranges of linear concentration. While the first linear range extends from 3.5 nmol L⁻¹ to 0.17 μmol L⁻¹, the second linear range was 0.4 μmol L⁻¹ to 40.1 μmol L⁻¹. The equations were obtained as iₚ (μA) = 73.659 × C_Rutin (μmol L⁻¹) + 2.0432 and iₚ (μA) = 3.4788 × C_Rutin (μmol L⁻¹) + 17.928, respectively. From the first linear range curve, LOD was found as 1.3 nmol L⁻¹ (S/N = 3). The CeO₂/MWCNT-CoPc/GCE presented satisfactory results for reproducibility, stability, and selectivity. This technique was able to quantify rutin in tablet forms with complete accuracy and precision.

Nanocrystalline spinel CoFe₂O₄ materials have been successfully synthesized by a facile force-driven chemical hydrolysis technique, and the impacts of varying post-synthesis annealing temperature on their morphological, structural, and electrochemical properties have been investigated. Microstructural investigation revealed the formation of a spinel cubic structure of a typical CoFe₂O₄ nanoparticle, which showed enhanced microstructural properties upon increasing annealing temperature. The optimally improved microstructure, coupled with the exhibition of favorable electrochemical and electrical properties of the CoFe₂O₄ sample annealed at 800 °C, resulted in an enhanced pseudocapacitive charge storage performance with maximum specific capacitance and capacity values of 756.5 Fg⁻¹ and 57.16 mAhg⁻¹. The presence of interstitial sites enabled fast and efficient ion transport and diffusion attributes for the high electrochemical charge storage outputs. The obtained results suggest that the effectiveness of CoFe₂O₄ as electrode materials for electrochemical energy storage depends on its microstructural build-up via thermal treatment variations.

The solid-state lithium battery is widely regarded as one of the most promising options for future energy storage systems. However, one significant challenge facing this type of battery is enhancing the ionic and electronic conductivities of the sintered composite cathode material as an active material. In this study, we investigated the ionic and electronic conductivities of a LiNi_0.7Mn_0.15Co_0.15O₂ compound that underwent dual modification through Al-doping and V₂O₅ coating, using AC impedance measurements. The ionic and electronic resistances were statistically analyzed via the Taguchi method, employing an experimental design focused on assessing the impact of these dual modifications on resistance reduction. An L8 orthogonal array was created, with Al-doping and V₂O₅ coating as factors, each with two levels: unmodified and modified. Each experiment was duplicated. The results, interpreted based on the calculated signal-to-noise ratio and confirmed by analysis of variance (ANOVA), demonstrated that dual modification has a statistically significant effect in reducing both ionic and electronic resistance. A significant increase in ionic and electronic conductivities was observed when the material was modified with Al-doping and V₂O₅ coating.