Energy & Environmental Materials最新文献

This work demonstrates a novel polymerization-derived polymer electrolyte consisting of methyl methacrylate, lithium bis(trifluoromethanesulfonyl)imide and fluoroethylene carbonate. The polymerization of MMA was initiated by the amino compounds following an anionic catalytic mechanism. LiTFSI plays both roles including the initiator and Li ion source in the polymer electrolyte. Normally, lithium bis(trifluoromethanesulfonyl)imide has difficulty in initiating the polymerization reaction of methyl methacrylate monomer, a very high concentration of lithium bis(trifluoromethanesulfonyl)imide is needed for initiating the polymerization. However, the fluoroethylene carbonate additive can work as a supporter to facilitate the degree of dissociation of lithium bis(trifluoromethanesulfonyl)imide and increase its initiator capacity due to the high dielectric constant. The as-prepared poly-methyl methacrylate-based polymer electrolyte has a high ionic conductivity (1.19 × 10⁻³ S cm⁻¹), a wide electrochemical stability window (5 V vs Li⁺/Li), and a high Li ion transference number ($��t_{{\mathrm{Li}}^{+}}�$) of 0.74 at room temperature (RT). Moreover, this polymerization-derived polymer electrolyte can effectively work as an artificial protective layer on Li metal anode, which enabled the Li symmetric cell to achieve a long-term cycling performance at 0.2 mAh cm⁻² for 2800 h. The LiFePO₄ battery with polymerization-derived polymer electrolyte-modified Li metal anode shows a capacity retention of 91.17% after 800 cycles at 0.5 C. This work provides a facile and accessible approach to manufacturing poly-methyl methacrylate-based polymerization-derived polymer electrolyte and shows great potential as an interphase in Li metal batteries.

Perovskite solar cells have emerged as a promising technology for renewable energy generation. However, the successful integration of perovskite solar cells with energy storage devices to establish high-efficiency and long-term stable photorechargeable systems remains a persistent challenge. Issues such as electrical mismatch and restricted integration levels contribute to elevated internal resistance, leading to suboptimal overall efficiency (η_overall) within photorechargeable systems. Additionally, the compatibility of perovskite solar cells with electrolytes from energy storage devices poses another significant concern regarding their stability. To address these limitations, we demonstrate a highly integrated photorechargeable system that combines perovskite solar cells with a solid-state zinc-ion hybrid capacitor using a streamlined process. Our study employs a novel ultraviolet-cured ionogel electrolyte to prevent moisture-induced degradation of the perovskite layer in integrated photorechargeable system, enabling perovskite solar cells to achieve maximum power conversion efficiencies and facilitating the monolithic design of the system with minimal energy loss. By precisely matching voltages between the two modules and leveraging the superior energy storage efficiency, our integrated photorechargeable system achieves a remarkable η_overall of 10.01% while maintaining excellent cycling stability. This innovative design and the comprehensive investigations of the dynamic photocharging process in monolithic systems, not only offer a reliable and enduring power source but also provide guidelines for future development of self-power off-grid electronics.

The undesirable capacity loss after first cycle is universal among layered cathode materials, which results in the capacity and energy decay. The key to resolving this obstacle lies in understanding the effect and origin of specific active Li sites during discharge process. In this study, focusing on Ah-level pouch cells for reliability, an ultrahigh initial Coulombic efficiency (96.1%) is achieved in an archetypical Li-rich layered oxide material. Combining the structure and electrochemistry analysis, we demonstrate that the achievement of high-capacity reversibility is a kinetic effect, primarily related to the sluggish Li mobility during oxygen reduction. Activating oxygen reduction through small density would induce the oxygen framework contraction, which, according to Pauli repulsion, imposes a great repulsive force to hinder the transport of tetrahedral Li. The tetrahedral Li storage upon deep oxygen reduction is experimentally visualized and, more importantly, contributes to 6% Coulombic efficiency enhancement as well as 10% energy density improvement for pouch cells, which shows great potentials breaking through the capacity and energy limitation imposed by intercalation chemistry.

The electrochemical coupling of biomass oxidation and nitrogen conversion presents a potential strategy for high value-added chemicals and nitrogen cycling. Herein, in this work, CuO/Co₃O₄ with heterogeneous interface is successfully constructed as a bifunctional catalyst for the electrooxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid and the electroreduction of nitrate to ammonia (NH₃). The open-circuit potential spontaneous experiment shows that more 5-hydroxymethylfurfural molecules are adsorbed in the Helmholtz layer of the CuO/Co₃O₄ composite, which certifies that the CuO/Co₃O₄ heterostructure is conducive to the kinetic adsorption of 5-hydroxymethylfurfural. In situ electrochemical impedance spectroscopy further shows that CuO/Co₃O₄ has faster reaction kinetics and lower reaction potential in oxygen evolution reaction and 5-hydroxymethylfurfural electrocatalytic oxidation. Moreover, CuO/Co₃O₄ also has a good reduction effect on $�{\mathrm{NO}}_3^{-}$. The ex-situ Raman spectroscopy shows that under the reduction potential, the metal oxide is reduced, and the generated Cu₂O can be used as a new active site for the reaction to promote the electrocatalytic conversion of $�{\mathrm{NO}}_3^{-}$ to NH₃ synthesis. This work provides valuable guidance for the synthesis of value-added chemicals by 5-hydroxymethylfurfural electrocatalytic oxidation coupled with $�{\mathrm{NO}}_3^{-}$ while efficiently producing NH₃.

To achieve high-energy-density and safe lithium-metal batteries (LMBs), solid-state electrolytes (SSEs) that exhibit fast Li-ion conductivity and good stability against lithium metal are of great importance. This study presents a systematic exploration of selenide-based materials as potential SSE candidates. Initially, Li₈SeN₂ and Li₇PSe₆ were selected from 25 ternary selenides based on their ability to form stable interfaces with lithium metal. Subsequently, their favorable electronic insulation and mechanical properties were verified. Furthermore, extensive theoretical investigations were conducted to elucidate the fundamental mechanisms underlying Li-ion migration in Li₈SeN₂, Li₇PSe₆, and derived Li₆PSe₅X (X = Cl, Br, I). Notably, the highly favorable Li-ion conduction mechanism of vacancy diffusion was identified in Li₆PSe₅Cl and Li₇PSe₆, which exhibited remarkably low activation energies of 0.21 and 0.23 eV, and conductivity values of 3.85 × 10⁻² and 2.47 × 10⁻² S cm⁻¹ at 300 K, respectively. In contrast, Li-ion migration in Li₈SeN₂ was found to occur via a substitution mechanism with a significant diffusion energy barrier, resulting in a high activation energy and low Li-ion conductivity of 0.54 eV and 3.6 × 10⁻⁶ S cm⁻¹, respectively. Throughout this study, it was found that the ab initio molecular dynamics and nudged elastic band methods are complementary in revealing the Li-ion conduction mechanisms. Utilizing both methods proved to be efficient, as relying on only one of them would be insufficient. The discoveries made and methodology presented in this work lay a solid foundation and provide valuable insights for future research on SSEs for LMBs.

In response to the ongoing energy crisis, advancing the field of electrocatalytic water splitting is of utmost significance, necessitating the urgent development of high-performance, cost-effective, and durable hydrogen evolution reaction catalysts. But the generated gas bubble adherence to the electrode surface and sluggish separation contribute to significant energy loss, primarily due to the insufficient exposure of active sites, thus substantially hindering electrochemical performance. Here, we successfully developed a superaerophobic catalytic electrode by loading phosphorus-doped nickel metal (NiP_x) onto various conductive substrates via an electrodeposition method. The electrode exhibits a unique surface structure, characterized by prominent surface fissures, which not only exposes additional active sites but also endows the electrode with superaerophobic properties. The NiP_x/Ti electrode demonstrates superior electrocatalytic activity for hydrogen evolution reaction, significantly outperforming a platinum plate, displaying an overpotential of mere 216 mV to achieve a current density of −500 mA cm⁻² in 1 M KOH. Furthermore, the NiP_x/Ti electrode manifests outstanding durability and robustness during continuous electrolysis, maintaining stability at a current density of −10 mA cm⁻² over a duration of 2000 h. Owing to the straightforward and scalable preparation methods, this highly efficient and stable NiP_x/Ti electrocatalyst offers a novel strategy for the development of industrial water electrolysis.

Organic perovskites are promising semiconductor materials for advanced photoelectric applications. Their fluorescence typically shows a negative temperature coefficient due to bandgap change and structural instability. In this study, a novel perovskite-based composite with positive sensitivity to temperature was designed and obtained based on its inverse temperature crystallization, demonstrating good flexibility and solution processability. The supercritical drying method was used to address the limitations of annealing drying in preparing high-performance perovskite. Optimizing the precursor composition proved to be an effective approach for achieving high fluorescence and structural integrity in the perovskite material. This perovskite-based composite exhibited a positive temperature sensitivity of 28.563% °C⁻¹ for intensity change and excellent temperature cycling reversibility in the range of 25–40 °C in an ambient environment. This made it suitable for use as a smart window with rapid response. Furthermore, the perovskite composite was found to offer temperature-sensing photoluminescence and flexible processability due to its components of perovskite-based compounds and polyethylene oxide. The organic precursor solvent could be a promising candidate for use as ink to print or write on various substrates for optoelectronic devices responding to temperature.

The ideal composite electrolyte for the pursued safe and high-energy-density lithium metal batteries (LMBs) is expected to demonstrate peculiarity of superior bulk conductivity, low interfacial resistances, and good compatibility against both Li-metal anode and high-voltage cathode. There is no composite electrolyte to synchronously meet all these requirements yet, and the battery performance is inhibited by the absence of effective electrolyte design. Here we report a unique “concentrated ionogel-in-ceramic” silanization composite electrolyte (SCE) and validate an electrolyte design strategy based on the coupling of high-content silane-conditioning garnet and concentrated ionogel that builds well-percolated Li⁺ transport pathways and tackles the interface issues to respond all the aforementioned requirements. It is revealed that the silane conditioning enables the uniform dispersion of garnet nanoparticles at high content (70 wt%) and forms mixed-lithiophobic-conductive LiF-Li₃N solid electrolyte interphase. Notably, the yielding SCE delivers an ultrahigh ionic conductivity of 1.76 × 10⁻³ S cm⁻¹ at 25 °C, an extremely low Li-metal/electrolyte interfacial area-specific resistance of 13 Ω cm², and a distinctly excellent long-term 1200 cycling without any capacity decay in 4.3 V Li||LiNi_0.5Co_0.2Mn_0.3O₂ (NCM523) quasi-solid-state LMB. This composite electrolyte design strategy can be extended to other quasi−/solid-state LMBs.

The structure–property relationship at interfaces is difficult to probe for thermoelectric materials with a complex interfacial microstructure. Designing thermoelectric materials with a simple, structurally-uniform interface provides a facile way to understand how these interfaces influence the transport properties. Here, we synthesized Bi_2−xSb_xTe₃ (x = 0, 0.1, 0.2, 0.4) nanoflakes using a hydrothermal method, and prepared Bi_2−xSb_xTe₃ thin films with predominantly (0001) interfaces by stacking the nanoflakes through spin coating. The influence of the annealing temperature and Sb content on the (0001) interface structure was systematically investigated at atomic scale using aberration-corrected scanning transmission electron microscopy. Annealing and Sb doping facilitate atom diffusion and migration between adjacent nanoflakes along the (0001) interface. As such it enhances interfacial connectivity and improves the electrical transport properties. Interfac reactions create new interfaces that increase the scattering and the Seebeck coefficient. Due to the simultaneous optimization of electrical conductivity and Seebeck coefficient, the maximum power factor of the Bi_1.8Sb_0.2Te₃ nanoflake films reaches 1.72 mW m⁻¹ K⁻², which is 43% higher than that of a pure Bi₂Te₃ thin film.

Solid oxide electrolysis cells (SOECs), displaying high current density and energy efficiency, have been proven to be an effective technique to electrochemically reduce CO₂ into CO. However, the insufficiency of cathode activity and stability is a tricky problem to be addressed for SOECs. Hence, it is urgent to develop suitable cathode materials with excellent catalytic activity and stability for further practical application of SOECs. Herein, a reduced perovskite oxide, Pr_0.35Sr_0.6Fe_0.7Cu_0.2Mo_0.1O_3-δ (PSFCM0.35), is developed as SOECs cathode to electrolyze CO₂. After reduction in 10% H₂/Ar, Cu and Fe nanoparticles are exsolved from the PSFCM0.35 lattice, resulting in a phase transformation from cubic perovskite to Ruddlesden–Popper (RP) perovskite with more oxygen vacancies. The exsolved metal nanoparticles are tightly attached to the perovskite substrate and afford more active sites to accelerate CO₂ adsorption and dissociation on the cathode surface. The significantly strengthened CO₂ adsorption capacity obtained after reduction is demonstrated by in situ Fourier transform-infrared (FT-IR) spectra. Symmetric cells with the reduced PSFCM0.35 (R-PSFCM0.35) electrode exhibit a low polarization resistance of 0.43 Ω cm² at 850 °C. Single electrolysis cells with the R-PSFCM0.35 cathode display an outstanding current density of 2947 mA cm⁻² at 850 °C and 1.6 V. In addition, the catalytic stability of the R-PSFCM0.35 cathode is also proved by operating at 800 °C with an applied constant current density of 600 mA cm⁻² for 100 h.