Search Results (145)

Rising incidents of critical lithium-ion battery (LIB) accidents highlight the pressing demand for safety enhancements that do not degrade the electrochemical performance parameters. This article provides a comprehensive overview of thermal failure mechanisms and thermal stability strategies, including their cathode, anode, separator, and electrolyte. The analysis covers the current thermal failure mechanisms of each component, including structural changes and boundary reactions, such as Mn dissolution in the cathode, solid–electrolyte interface decomposition in the anode, the melting–shrinkage–perforation of the separator, as well as decomposition–combustion–gas generation in the electrolyte. Furthermore, the article reviews thermal stability improvement methods for each component, including element doping and surface coating of the electrode, high-temperature resistance, flame retardancy, and porosity strategies of the separator, flame retardant, non-flammable solvent, and solid electrolyte strategies of the electrolyte. The findings highlight that incorporating diverse elements into the crystal lattice enhances the thermal stability and extends the service life of electrode materials, while applying surface coatings effectively suppresses the boundary reactions and structural degradation responsible for thermal failure. Furthermore, by using solid electrolytes such as polymer electrolytes, and combining innovative ceramic-polymer composite separators, it is possible to effectively reduce the flammability of these components and enhance their thermal stability. As a result, the overall thermal safety of LIBs is improved. These strategies collectively contribute to the overall thermal safety performance of LIBs. Full article

Surface microstructure of grains vastly decides the electrochemical performance of nickel-rich oxide cathodes, which can improve their interfacial kinetics and structural stability to realize their further popularization. Herein, taking the representative LiNi_0.8Co_0.15Al_0.05O₂ (NCA) materials as an example, a surface heterojunction structure construction strategy to enhance the interface characteristics of high-nickel materials by introducing interfacial ZnO sites has been designed (NCA@ZnO). Impressively, this heterointerface creates a strong built-in electric field, which significantly improves electron/Li-ion diffusion kinetics. Concurrently, the ZnO layer acts as an effective physical barrier against electrolyte corrosion, notably suppressing interfacial parasitic reactions and ultimately optimizing the structure stability of NCA@ZnO. Benefiting from synchronous optimization of interface stability and kinetics, NCA@ZnO exhibits advanced cycling performance with the capacity retention of 83.7% after 160 cycles at a superhigh rate of 3 C during 3.0–4.5 V. The prominent electrochemical performance effectively confirms that the surface structure design provides a critical approach toward obtaining high-performance cathode materials with enhanced long-cycling stability. Full article

Electrochemical treatment by means of direct current (DC) is usually used as a measure for steel rebar corrosion protection, e.g., cathodic protection (CP), electrochemical chloride extraction (ECE), and re-alkalization (RA). However, the passage of an electrical charge through the pore system of concrete or mortar, coupled with the migration of ions, concentration changes, and resulting phase changes, may alter its chloride penetration resistance and, subsequently, the time until rebar corrosion activation. Porosity changes in hardened Portland cement mortar were studied by means of mercury intrusion porosimetry (MIP) and electrochemical impedance spectroscopy (EIS), and alterations in the mortar surface phase composition were observed by means of X-ray diffraction (XRD). In order to innovatively investigate the impact of DC treatment on the properties of the mortar–electrolyte interface, the cathode-facing mortar surface and the anode-facing mortar surface were analyzed separately. The corrosion of steel coupons embedded in DC-treated hardened mortar was monitored by means of the free corrosion potential (E_oc) and polarization resistance (R_p). The results showed that the DC treatment affected the surface porosity of the hardened Portland cement mortar at the nanoscale. Up to two-thirds of the small pores (0.001–0.01 µm) were replaced by medium-sized pores (0.01–0.06 µm), which may be significant for chloride ingress. Although the porosity and phase composition alterations were confirmed using other techniques (EIS and XRD), corrosion tests revealed that they did not significantly affect the time until the corrosion activation of the steel coupons in the mortar. Full article

The development of high-performance and stable solid-state lithium batteries (SSBs) is critical for advancing next-generation energy storage technologies. This study investigates LATP (Li_1.3Al_0.3Ti_1.7(PO₄)₃) coatings to enhance the electrochemical performance and interface stability of NCMA83 (LiNi_0.83Co_0.06Mn_0.06Al_0.05O₂) cathodes. Compared to conventional combinations with LPSC (Li₆PS₅Cl) solid electrolytes, LATP coatings significantly reduce interfacial reactivity and improve cycling stability. Structural and morphological analyses reveal that LATP coatings maintain the crystallinity of NCMA83 while fine-tuning its lattice stress. Electrochemical testing demonstrates that LATP-modified samples (83L5) achieve superior capacity retention (65 mAh/g after 50 cycles) and reduced impedance (R_ct ~200 Ω), compared to unmodified samples (83L0). These results highlight LATP’s potential as a surface engineering solution to mitigate degradation effects, enhance ionic conductivity, and extend the lifespan of high-capacity SSBs. Full article

Nickel-rich layered oxides such as LiNi_xMn_yCo_zO₂ (NMC), LiNi_xCo_yAl_zO₂ (NCA), and LiNi_xMn_yCo_zAl_{(1–x–y–z)}O₂ (NMCA), where x ≥ 0.6, have emerged as key cathode materials in lithium-ion batteries due to their high operating voltage and superior energy density. These materials, characterized by low cobalt content, offer a promising path toward sustainable and cost-effective energy storage solutions. However, their electrochemical performance remains below theoretical expectations, primarily due to challenges related to structural instability, limited thermal safety, and suboptimal cycle life. Intensive research efforts have been devoted to addressing these issues, resulting in substantial performance improvements and enabling the development of next-generation lithium-ion batteries with higher nickel content and reduced cobalt dependency. In this review, we present recent advances in material design and engineering strategies to overcome the problems limiting their electrochemical performance (cation mixing, phase stability, oxygen release, microcracks during cycling). These strategies include synthesis methods to optimize the morphology (size of the particles, core–shell and gradient structures), surface modifications of the Ni-rich particles, and doping. A detailed comparison between these strategies and the synergetic effects of their combination is presented. We also highlight the synergistic role of compatible lithium salts and electrolytes in achieving state-of-the-art nickel-rich lithium-ion batteries. Full article

Silicon oxide–graphite is a promising high-capacity anode material for next-generation lithium-ion batteries (LIBs). However, despite using a small fraction (≤5%) of Si, it suffers from a short cycle life owing to intrinsic swelling and particle pulverization during cycling, making practical application challenging. High-nickel (Ni ≥ 80%) oxide cathodes for high-energy-density LIBs and their operation beyond 4.2 V have been pursued, which requires the anodic stability of the electrolyte. Herein, we report a nonflammable multi-functional fluorinated ester–based liquid electrolyte that stabilizes the interfaces and suppresses the swelling of highly loaded 5 wt% SiO–graphite anode and LiNi_0.88Co_0.08Mn_0.04O₂ cathode simultaneously in a 3.5 mAh cm⁻² full cell, and improves cycle life and battery safety. Surface characterization results reveal that the interfacial stabilization of both the anode and cathode by a robust and uniform solid electrolyte interphase (SEI) layer, enriched with fluorinated ester-derived inorganics, enables 80% capacity retention of the full cell after 250 cycles, even under aggressive conditions of 4.35 V, 1 C and 45 °C. This new electrolyte formulation presents a new opportunity to advance SiO-based high-energy density LIBs for their long operation and safety. Full article

This work presents a comprehensive investigation into the interfacial charge storage mechanisms and lithium-ion transport behavior of Li-metal all-solid-state batteries (ASSBs) employing LiFePO₄ (LFP) cathodes fabricated via alternating current electrophoretic deposition (AC-EPD) and Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) as the solid-state electrolyte. We demonstrate that optimal sintering improves the LATP–LFP interfacial contact, leading to higher lithium diffusivity (~10⁻⁹ cm²∙s⁻¹) and diffusion-controlled kinetics (b ≈ 0.5), which directly translate to better rate capability. Structural and electrochemical analyses—including X-ray diffraction, scanning electron microscopy, cyclic voltammetry, and rate capability tests—demonstrate that the cell with LATP sintered at 900 °C delivers the highest Li-ion diffusivity (~10⁻⁹ cm²∙s⁻¹), near-ideal diffusion-controlled behavior (b-values ~0.5), and superior rate capability. In contrast, excessive sintering at 1000 °C led to reduced diffusivity (~10⁻¹⁰ cm²∙s⁻¹). The liquid electrolyte system showed higher b-values (~0.58), indicating the inclusion of surface capacitive behavior. The correlation between b-values, diffusivity, and morphology underscores the critical role of interface engineering and electrolyte processing in determining the performance of solid-state batteries. This study establishes AC-EPD as a viable and scalable method for fabricating additive-free LFP cathodes and offers new insights into the structure–property relationships governing the interfacial transport in ASSBs. Full article

Manganese oxides (MnO_x) have been confirmed as the most promising candidates for aqueous zinc-ion batteries (AZIBs) due to their cost-effectiveness, high theoretical capacity, high voltage platforms, and environmental friendliness. However, in practical applications, AZIBs are hindered by the Jahn–Teller distortion (JTD) effect, primarily induced by Mn³⁺ (t_2g³e_g¹) in octahedral coordination, which leads to severe structural deformation, rapid capacity fading, and poor cycling stability. This review systematically outlines the fundamental mechanisms of JTD in MnO_x cathodes, including electronic structure changes, lattice distortions, and their side effects on Zn²⁺ storage performance. Furthermore, we critically discuss advanced strategies to suppress JTD, such as cation/anion doping, interlayer engineering, surface/interface modification, and electrolyte optimization, aimed at enhancing both structural stability and electrochemical performance. Finally, we propose future research directions, such as in situ characterization, machine learning-guided material design, and multifunctional interfacial engineering, to guide the design of high-performance MnO_x hosts for next-generation AZIBs. This review may provide a promising guideline for overcoming JTD challenges and advancing MnO_x-based energy storage systems. Full article

In this study, we couple precise interface engineering via alternating current electrophoretic deposition (AC–EPD) with performance-enhancing structural transformation via annealing, enabling the development of high-performance, stable, and tunable Mn-based cathodes for aqueous zinc-ion batteries (ZIBs). Using AC–EPD to fabricate Mn(BTC) (BTC = 1,3,5-benzenetricarboxylic acid) cathodes followed by thermal annealing to synthesize MOF-derived Mn₃O₄ offers a synergistic approach that addresses several key challenges in aqueous ZIB systems. The Mn₃O₄ cathode prepared via AC–EPD from Mn(BTC) exhibited a remarkable specific capacity of up to 430 mAh/g at a current density of 200 mA/g. Interestingly, the capacity continued to increase progressively with cycling, suggesting dynamic structural or interfacial changes that improved Zn²⁺ transport and utilization over time. Such capacity enhancement behavior during prolonged cycling at elevated rates has not been observed in previously reported Mn₃O₄-based ZIB systems. Kinetic analysis further revealed that the charge storage process is predominantly governed by diffusion-controlled mechanisms. This behavior can be attributed to the intrinsic characteristics of the Mn₃O₄ phase formed from the MOF precursor, where the bulk redox reactions involving Zn²⁺ insertion require ion migration into the electrode interior. Even though the electrode was processed as an ultrathin film with enhanced electrolyte contact, the charge storage remains limited by solid-state ion diffusion rather than fast surface-driven reactions, reinforcing the diffusion-dominant nature of the system. Full article

In this study, a Zn(CN)₂–V₂O₃–C composite cathode was synthesized via AC electrophoretic deposition (EPD) and evaluated for application in aqueous zinc-ion batteries (ZIBs). Here, we report for the first time a binder-free Zn(CN)₂–V₂O₃–C composite cathode, using AC-EPD to create an ultrathin architecture optimized for probing the electrode–electrolyte interface without interference from additives or bulk effects. The composite combines Zn(CN)₂ for structural support, V₂O₃ as the redox-active material, and carbon for improved conductivity. X-ray diffraction confirmed the presence of Zn(CN)₂ and V₂O₃ phases, while scanning electron microscopy revealed a uniform, ultrathin film morphology. Electrochemical analysis demonstrated a hybrid charge storage mechanism with a b-value of 0.64, indicating both capacitive and diffusion-controlled contributions. The electrode delivered a high specific capacity (~250 mAh/g at 500 mA/g) with stable cycling performance. These results highlight the potential of metal–organic framework-derived composites for high-performance ZIB cathodes. The composite is especially effective when prepared via AC-EPD, which yields ultrathin, uniform films with strong adhesion and low agglomeration. This enhances energy storage performance and provides a reliable platform for focusing on interfacial charge storage, excluding the effect of binders on electrochemical performance. Full article

Exploring advanced sulfur cathode materials is important for the development of lithium-sulfur batteries (LSBs), but they still present challenges. Herein, zinc oxide dots-modified vanadium nitride flower-like heterojunctions (Zn-QDs-VN) as sulfur hosts are prepared by a phase separation strategy. Characterizations confirm that the flower structure with high specific surface area and pores improves active site exposure and electron/mass transfer. In situ phase separation enriches the Zn-QDs-VN interface, addressing the issues of uneven distribution and interface reduction of Zn-QDs-VN. Further theoretical computations reveal that ZnO-QDs-VN with optimized intermediate spin states can constitute a stable LiS* bond sequence, which can conspicuously facilitate the adsorption and conversion of LiPSs and reduce the battery reaction energy barrier. Therefore, the ZnO-QDs-VN@S cathode shows a high initial specific capacity of 1109.6 mAh g⁻¹ at 1.0 C and long cycle stability (maintaining 984.2 mAh g⁻¹ after 500 cycles). Under high S loading (8.5 mg cm⁻²) and lean electrolyte conditions (E/S = 6.5 μL mg⁻¹), it also exhibits a high initial area capacity (10.26 mAh cm⁻²) at 0.2 C. The interfacial synergistic effect accelerates the adsorption and conversion of LiPSs and reduces the energy barriers in cell reactions. The study provides a new method for designing heterojunctions to achieve high-performance LSBs. Full article

This study evaluates the tribological behavior of two elastomeric sealing materials—EPDM and TPV—sliding against 30 wt.% glass fiber-reinforced polyamide 66 (PA66GF30), a composite widely used in structural and guiding components. The application context is low-leakage valve systems in polymer electrolyte membrane fuel cells (PEMFCs), particularly on the cathodic (air) side, where dry contact and low-friction sealing are critical. Pin-on-disk tests were conducted under three normal loads (1, 3, and 6 N) and sliding speeds of approximately 0.05, 0.10, and 0.15 m/s (92, 183, and 286 RPM). The coefficient of friction (CoF), mass loss, and wear morphology were analyzed. TPV generally exhibited lower and more stable friction than EPDM, with CoF values exceeding 1.0 at 1 N but falling within 0.32–0.52 under typical operating conditions (≥3 N). EPDM reached a maximum mass loss of 0.060%, while TPV remained below 0.022%. Microscopy revealed more severe wear features in EPDM, including tearing and abrasive deformation, whereas TPV surfaces displayed smoother, more uniform wear consistent with its dual-phase morphology. These findings support the selection of TPV over EPDM in dry-contact sealing interfaces involving composite counterfaces in PEMFC systems. Full article

Hematite (Fe₂O₃) has been accepted as a promising and potential photo(electro)catalyst. However, its poor carrier separation and transfer efficiency has limited its application for photoelectrocatalytic (PEC) water oxidation. Herein, a S-doped FeOOH (S:FeOOH) layer was rationally designed and grown on Fe₂O₃ to construct a S:FeOOH/Fe₂O₃ composite photoanode. The obtained S:FeOOH/Fe₂O₃ photoanodes were fully characterized. The surface injection efficiency for Fe₂O₃ was then significantly increased with a high η_surface value of 92.8%, which increases to 2.98 times for Fe₂O₃ and 2.16 times for FeOOH/Fe₂O₃, respectively. With 2.43 mA cm^‒2 at 1.23 V, the optimized S:FeOOH/Fe₂O₃ photoanode was entrusted with a higher photocurrent density. The onset potential for S:FeOOH/Fe₂O₃ cathodically shifts 70 mV over Fe₂O₃. The improved PEC performance suggests that the S:FeOOH layer acts as ultrafast transport channels for holes at the photoanode/electrolyte interface, suppressing surface charge recombination. A Z-scheme band alignment between Fe₂O₃ and S:FeOOH was deduced from the UV–Vis and UPS spectra to promote charge transfer. This method provides an alternative for the construction of photoanodes with enhanced PEC water splitting performance. Full article

Anode-free lithium-ion batteries offer a volumetric energy density approximately 60% higher than that of conventional lithium-ion cells. Despite this advantage, they often experience rapid capacity degradation and a limited cycle life. Optimizing electrolyte formulations—particularly through the use of specific additives, solvents, and lithium salts—is essential to improving these systems. This study explores electrolytes composed of fluorinated and carbonate-based solvents applied in anode-free lithium-ion cells featuring copper as the anode substrate and Li_1.05Ni_0.33Mn_0.33Co_0.33O₂ as the cathode. In the present work, the ionic conductivity of electrolytes was studied by impedance spectroscopy, and the electrochemical parameters of anode-free lithium-ion cells were compared using these electrolyte solutions: lithium difluoro(oxalato)borat (LIDFOB) salts were used in a mixture of solvents such as fluoroethylene carbonate (FEC) and dimethoxyethane (DME) in a ratio of 3:7 and in a mixture of propylene carbonate (PC) and dimethoxyethane in a ratio of 3:7. Enhanced performance was observed upon the substitution of conventional carbonates with fluorinated co-solvents. The findings suggest that LiDFOB is a thermostable salt, and its high conductivity contributes to the formation and stabilization of the interface of solid electrolytes. The results indicate that at low temperature conditions, a double salt should be used for lithium current sources, for example, 0.4 M LiDFOB and 0.6 M LiBF₄, as well as electrolyte additives such as fluoroethylene carbonate and lithium nitrate. 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