ACS Applied Energy Materials最新文献

Conventional polyolefin separators in lithium-ion batteries (LIBs) suffer from poor electrolyte affinity, limited thermal stability, and insufficient resistance to dendrite penetration, which critically constrain battery safety and durability. Here, we report a multifunctional electrospun electrospun polyacrylonitrile (PAN)/poly(ether imide) (PEI)/boehmite (BM) composite separator. Uniformly dispersed BM nanoparticles, enriched with surface─OH groups, establish strong interfacial interactions with polymer chains, thereby reinforcing the fiber matrix, acting as rigid barriers to effectively block dendrite penetration, and simultaneously enhancing electrolyte wettability. The resulting continuous three-dimensional porous network maintains structural integrity upon prolonged electrolyte exposure, providing stable Li⁺ transport channels, swelling tolerance, and superior thermo-mechanical robustness, as evidenced by a tensile strength of 13.7 MPa (compared to 5.1 MPa for pure PAN). Benefiting from this structural design, Li||Li symmetric cells operate stably for over 600 h at 0.5 mA·cm^–2 with suppressed dendrite growth, while Li||Lithium Manganese Oxide (LiMnO₂) half-cells deliver excellent rate performance and retain 90.1% of capacity after 400 cycles at 1.0C. This work demonstrates a simple yet effective separator design strategy, offering new insights into the development of swelling-tolerant and dendrite-resistant separators for safe and durable LIBs.

Redox-targeting flow batteries (RTFBs) offer a way to boost the energy density of traditional flow batteries. In RTFBs, solid materials need to be mixed with binders to form granules, and the utilization of these solid materials hinges on the granule’s preparation method. However, so far, this preparation method has not been well-designed, preventing the full realization of RTFBs’ high-energy-density potential. This study presents a phase-inversion granulation approach to create high-porosity and high-tortuosity granules for RTFBs. Spherical granules made by this method had a porosity of 69.44%. As a result, the utilization of LiFePO₄ granules in RTFBs is increased to over 99.5%, the highest reported value. CT and FIB-SEM characterizations were used to clarify the 3D model of the porous granules. Furthermore, a zinc-based RTFB with LiFePO₄ granules in the cathodic tank achieved an energy density of 122.1 Wh/L and a capacity retention rate of over 94% of its initial capacity after 140 h of continuous charge–discharge. This research offers a strategy for fabricating high-utilization granules for RTFBs.

Halide solid electrolytes (SEs) are a strong candidate for next-generation lithium-based solid-state batteries for their potential to possess a balance of key properties including ionic conductivity, mechanical properties, and electrochemical stability window (ESW) and can be synthesized using environmentally friendly processes. However, there is a lack of halides simultaneously fulfilling all the mentioned key properties, and searching for the right candidates via experiments is proven challenging. In this work, we develop a computational approach combining machine learning (ML) and DFT calculations, to discover promising halide SEs that satisfy several bulk properties via multiproperty predictions. Various ML and deep learning (DL) models are compared to predict ionic conductivity, bulk and shear moduli, and ESW. The CatBoost, Light Gradient Boosting (LGBM), and Skorch Neural Network (NN) models are found to yield high prediction accuracies for the mentioned properties, with minimum average classification accuracies and average R² scores exceeding 80% and 0.70, respectively. DFT verifications are performed on Rb₂LiBiCl₆, LiHF₂, and Rb₂LiAlF₆, with the results suggesting Rb₂LiAlF₆ as a promising candidate for high voltage battery applications. Overall, we demonstrate that the current ML + DFT approach is useful in screening potential halide solid-state electrolytes that can satisfy several key SE properties.

Electrochemical attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) has emerged as a powerful technique for obtaining molecular-level insights into interfacial reaction mechanisms. In this spectroelectrochemical method, the island-like metal film cast on internal reflection elements (IREs) governs surface sensitivity, stability, and compatibility with electrochemical systems. Historically, materials such as Si, Ge, and ZnSe have been widely used as IREs due to their favorable optical properties. However, limitations, including chemical instability and limited enhancement factors, have driven the exploration of advanced materials. In this mini review, we summarize recent progress in the development of composite windows and IRE materials aimed at achieving broader detection frequency ranges, greater chemical robustness, and enhanced spectral signal-to-noise ratios. Representative applications of wide-frequency ATR-SEIRAS investigations across a broad pH range in electrocatalysis and electroplating are also discussed. Finally, we offer perspectives on the future development of IRE materials and techniques to further enhance the capabilities of in situ ATR-SEIRAS for studying complex interfacial electrochemical processes.

In response to the global energy crisis and growing environmental awareness, lithium–sulfur batteries (LSBs) have attracted considerable attention as a promising candidate for energy storage systems due to their high theoretical energy density. Nevertheless, the practical application of LSBs is impeded by the polysulfide-induced “shuttle effect” (Li₂S_n, where n = 2–8) and the poor electrical conductivity of elemental sulfur (S₈) and lithium sulfide (Li₂S). To mitigate these challenges, this study introduces a WSe₂@NCNFs interlayer synthesized by compositing WSe₂ with nitrogen-doped carbon nanofibers (NCNFs) through electrospinning. This composite not only stabilizes the two-dimensional (2D) WSe₂ structure with substantial catalytic activity but also facilitates the growth of WSe₂ on carbon nanosurfaces with abundant exposed (100) crystal planes and grain boundaries. These characteristics significantly enhance lithium polysulfides (LiPSs) adsorption and catalytic conversion while providing extensive nucleation sites for Li₂S. Experimental results indicate that batteries utilizing the WSe₂@NCNFs interlayer exhibit superior cycling stability and rate performance. This crystal engineering strategy presents an innovative approach to enhancing the overall performance of LSBs.

Single-crystal Ni-rich LiNi_xCo_yMn_zO₂ (SC-NCM) cathodes deliver high capacity but suffer from severe interfacial degradation. Here, a lithiated starlike molecule, lithium 3-mercaptopropanesulfonyl-trifluoromethanesulfonylimide-triallyl phosphite (M-TLP), is designed as a functional interlayer for SC-NCM811. Wet-coated M-TLP forms a uniform ∼6 nm layer, whose starlike structure enables dense coverage and accommodates volume change. Sulfonylimide groups and in-situ LiF enhance Li⁺ dissociation and transport. Consequently, Li||M-TLP@SC-NCM811 achieves 57.68% capacity retention at 1 C for 500 cycles (vs 30.69%) and a 12.82% higher 5 C discharge capacity. This molecularly engineered coating stabilizes high-voltage cathodes and accelerates interfacial Li⁺ transport.

The development of next-generation energy materials is pivotal for addressing global energy demands and achieving sustainable, carbon-neutral power solutions. Hydroelectric cells (HECs), which generate clean energy via water dissociation, offer a promising pathway for energy generation. This study employs gamma irradiation as an effective defect-engineering approach to enhance the performance of cobalt ferrite (CoFe₂O₄)-based HECs. CoFe₂O₄ was synthesized via a solid-state route and subjected to gamma doses of 0, 20, 50, 100, and 200 kGy. X-ray diffraction confirmed the cubic spinel phase, while irradiation reduced crystallite size and increased lattice strain and structural disorder, as evidenced by peak broadening, elevated Urbach energy, and high-resolution transmission electron microscopy observed defects. X-ray photoelectron spectroscopy revealed substantial cationic redox transitions (Fe³⁺ → Fe²⁺, Co²⁺ → Co³⁺) accompanied by marked rise in the oxygen vacancy concentration from 19% to 32% at 100 kGy. These irradiation-induced defects serve as active sites for water adsorption and dissociation, thereby boosting the ionic conductivity and accelerating electrochemical kinetics. Consequently, the offload current density and power density of the HECs improved nearly 3-fold, achieving 7.18 mA/cm² and 0.76 mW/cm², respectively. This study underscores gamma irradiation as a powerful strategy to tailor defect landscapes and cation valence states in CoFe₂O₄ for sustainable green energy generation systems.

Spin polarization strongly influences charge carrier dynamics. Density functional theory calculations show that transition metal doping obviously changes spin polarization. Co doping induces negligible changes, while Cu- and Fe-dopings change the spin polarization from nonspin to low- and high-spin, respectively. The enhanced spin polarization causes spin–orbit coupling and electron spin flip, suppressing nonradiative charge recombination. Fe:BiVO₄ exhibits the strongest spin polarization. Experimental degradation of tetracycline hydrochloride confirms that Fe:BiVO₄ exhibits superior photocatalytic activity, consistent with theoretical predictions. This study uncovered the mechanism of spin polarization on photocatalytic activity and provided valuable principle for efficient photocatalysts.

Methanol oxidation-assisted water electrolysis offers the dual benefit of producing hydrogen fuel at the cathode and valuable formate at the anode. However, the methanol oxidation reaction (MOR) often suffers from slow kinetics, which are largely governed by the catalyst’s redox characteristics. Therefore, designing highly active MOR electrocatalysts requires careful tuning of their redox properties. Herein, we develop a nitrogen-modified Ni⁰/Ni(OH)₂ [denoted as N@Ni] heterojunction as an efficient MOR electrocatalyst. The N@Ni demonstrated an MOR current density of 10 mA cm^–2 at a potential of 1.38 V vs RHE, smaller than the 1.47 V vs RHE required by pristine Ni prepared without N-modification. Nitrogen modification induced surface distortion and altered electronic features of the catalyst, thereby facilitating the adsorption and desorption of reactive intermediates. Experimental results demonstrated that N-doping not only altered the Ni²⁺/Ni³⁺ redox behavior and reaction pathway but also lowered the activation energy for both OER and MOR. In situ electrochemical impedance spectroscopy confirmed enhanced charge transfer and faster reaction kinetics upon nitrogen incorporation, while in situ Raman analysis highlighted the active participation of electro-generated Ni³⁺ species during MOR.

Te-free Bi₂S₃-based thermoelectric (TE) materials present compelling prospects for ecofriendly and industrial scale-up applications, owing to their earth-abundant constituents, cost-effectiveness, and intrinsic nontoxicity. However, their low figure of merit (ZT) restricts their practical applications. In this study, both experiments and density functional theory calculations reveal that donor–acceptor PbCl₂ can simultaneously improve its electrical and thermal properties. In Bi₂S₃, Cl acts as the donor while Pb serves as the acceptor, and their competitive relationship leads to a trade-off between σ and S, thus increasing the power factor. Dense nanoscale structures (nanodomains) with the same structure but different light and dark paths, derived from the chemical composition fluctuation, are embedded in the PbCl₂-incorporated Bi₂S₃ matrix. Such a special structure leads to a low κ_lat of ∼0.33 W m^–1 K^–1 in the Bi₂S₃-1.5% PbCl₂ sample. As a result, a rather high ZT value of ∼0.82 at 673 K and an average ZT of 0.46 at 323–673 K are obtained for the PbCl₂-incorporated Bi₂S₃ sample, resulting in the superior TE performance of Bi₂S₃-based bulks. This work provides an effective strategy for enhancing TE properties in Bi₂S₃ semiconductors by nanodomain engineering.