能源化学最新文献

The sluggish kinetics of the oxygen reduction reaction (ORR) is the bottleneck for various electrochemical energy conversion devices. Regulating the electronic structure of electrocatalysts by ligands has received particular attention in deriving valid ORR electrocatalysts. Here, the surface electronic structure of Pt-based noble metal aerogels (NMAs) was modulated by various organic ligands, among which the electron-withdrawing ligand of 4-methylphenylene effectively boosted the ORR electrocatalysis. Theoretical calculations suggested the smaller energy barrier for the transformation of O* to OH* and downshift the d-band center of Pt due to the interaction between 4-methylphenylene and the surface metals, thus enhancing the ORR intrinsic activity. Both Pt₃Ni and PtPd aerogels with 4-methylphenylene decoration performed significant enhancement in ORR activity and durability in different media. Remarkably, the 4-methylphenylene modified PtPd aerogel exhibited the higher half-wave potential of 0.952 V and the mass activity of 10.2 times of commercial Pt/C. This work explained the effect of electronic structure on ORR electrocatalytic properties and would promote functionalized NMAs as efficient ORR electrocatalysts.

Building well-developed ion-conductive highways is highly desirable for anion exchange membranes (AEMs). Grafting side chain is a highly effective approach for constructing a well-defined phase-separated morphological structure and forming unblocked ion pathways in AEMs for fast ion transport. Fluorination of side chains can further enhance phase separation due to the superhydrophobic nature of fluorine groups. However, their electronic effect on the alkaline stability of side chains and membranes is rarely reported. Here, fluorine-containing and fluorine-free side chains are introduced into the polyaromatic backbone in proper configuration to investigate the impact of the fluorine terminal group on the stability of the side chains and membrane properties. The poly(binaphthyl-co-p-terphenyl piperidinium) AEM (QBNpTP) has the highest molecular weight and most dimensional stability due to its favorable backbone arrangement among ortho- and meta-terphenyl based AEMs. Importantly, by introducing both a fluorinated piperidinium side chain and a hexane chain into the p-terphenyl-based backbone, the prepared AEM (QBNpTP-QFC) presents an enhanced conductivity (150.6 mS cm⁻¹) and a constrained swelling at 80 °C. The electronic effect of fluorinated side chains is contemplated by experiments and simulations. The results demonstrate that the presence of strong electro-withdrawing fluorine groups weakens the electronic cloud of adjacent C atoms, increasing OH⁻ attack on the C atom and improving the stability of piperidinium cations. Hence QBNpTP-QFC possesses a robust alkaline stability at 80 °C (95.3% conductivity retention after testing in 2 M NaOH for 2160 h). An excellent peak power density of 1.44 W cm⁻² and a remarkable durability at 80 °C (4.5% voltage loss after 100 h) can be observed.

Transition metal-nitrogen-carbon (M-N-C) as a promising substitute for the conventional noble metal-based catalyst still suffers from low activity and durability for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). To tackle the issue, herein, a new type of sulfur-doped iron-nitrogen-hard carbon (S-Fe-N-HC) nanosheets with high activity and durability in acid media were developed by using a newly synthesized precursor of amide-based polymer with Fe ions based on copolymerizing two monomers of 2, 5-thiophene dicarboxylic acid (TDA) as S source and 1, 8-diaminonaphthalene (DAN) as N source via an amination reaction. The as-synthesized S-Fe-N-HC features highly dispersed atomic FeN_x moieties embedded into rich thiophene-S doped hard carbon nanosheets filled with highly twisted graphite-like microcrystals, which is distinguished from the majority of M-N-C with soft or graphitic carbon structures. These unique characteristics endow S-Fe-N-HC with high ORR activity and outstanding durability in 0.5 M H₂SO₄. Its initial half-wave potential is 0.80 V and the corresponding loss is only 21 mV after 30,000 cycles. Meanwhile, its practical PEMFC performance is a maximum power output of 628.0 mW cm⁻² and a slight power density loss is 83.0 mW cm⁻² after 200-cycle practical operation. Additionally, theoretical calculation shows that the activity of FeN_x moieties on ORR can be further enhanced by sulfur doping at meta-site near FeN₄C. These results evidently demonstrate that the dual effect of hard carbon substrate and S doping derived from the precursor platform of amid-polymers can effectively enhance the activity and durability of Fe-N-C catalysts, providing a new guidance for developing advanced M-N-C catalysts for ORR.

With the depletion of fossil fuels and the demand for high-performance energy storage devices, solid-state lithium metal batteries have received widespread attention due to their high energy density and safety advantages. Among them, the earliest developed organic solid-state polymer electrolyte has a promising future due to its advantages such as good mechanical flexibility, but its poor ion transport performance dramatically limits its performance improvement. Therefore, single-ion conducting polymer electrolytes (SICPEs) with high lithium-ion transport number, capable of improving the concentration polarization and inhibiting the growth of lithium dendrites, have been proposed, which provide a new direction for the further development of high-performance organic polymer electrolytes. In view of this, lithium ions transport mechanisms and design principles in SICPEs are summarized and discussed in this paper. The modification principles currently used can be categorized into the following three types: enhancement of lithium salt anion-polymer interactions, weakening of lithium salt anion-cation interactions, and modulation of lithium ion-polymer interactions. In addition, the advances in single-ion conductors of conventional and novel polymer electrolytes are summarized, and several typical high-performance single-ion conductors are enumerated and analyzed in what way they improve ionic conductivity, lithium ions mobility, and the ability to inhibit lithium dendrites. Finally, the advantages and design methodology of SICPEs are summarized again and the future directions are outlined.

The unabated carbon dioxide (CO₂) emission into the atmosphere has exacerbated global climate change, resulting in extreme weather events, biodiversity loss, and an intensified greenhouse effect. To address these challenges and work toward carbon (C) neutrality and reduced CO₂ emissions, the capture and utilization of CO₂ have become imperative in both scientific research and industry. One cutting-edge approach to achieving efficient catalytic performance involves integrating green bioconversion and chemical conversion. This innovative strategy offers several advantages, including environmental friendliness, high efficiency, and multi-selectivity. This study provides a comprehensive review of existing technical routes for carbon sequestration (CS) and introduces two novel CS pathways: the electrochemical-biological hybrid and artificial photosynthesis systems. It also thoroughly examines the synthesis of valuable C_n products from the two CS systems employing different catalysts and biocatalysts. As both systems heavily rely on electron transfer, direct and mediated electron transfer has been discussed and summarized in detail. Additionally, this study explores the conditions suitable for different catalysts and assesses the strengths and weaknesses of biocatalysts. We also explored the biocompatibility of the electrode materials and developed novel materials. These materials were specifically engineered to combine with enzymes or microbial cells to solve the biocompatibility problem, while improving the electron transfer efficiency of both. Furthermore, this review summarizes the relevant systems developed in recent years for manufacturing different products, along with their respective production efficiencies, providing a solid database for development in this direction. The novel chemical-biological combination proposed herein holds great promise for the future conversion of CO₂ into advanced organic compounds. Additionally, it offers exciting prospects for utilizing CO₂ in synthesizing a wide range of industrial products. Ultimately, the present study provides a unique perspective for achieving the vital goals of “peak shaving” and C-neutrality, contributing significantly to our collective efforts to combat climate change and its associated challenges.

Exploring effective iridium (Ir)-based electrocatalysts with stable iridium centers is highly desirable for oxygen evolution reaction (OER). Herein, we regulated the incorporation manner of Ir in Co₃O₄ support to stabilize the Ir sites for effective OER. When anchored on the surface of Co₃O₄ in the form of Ir(OH)₆ species, the created Ir-OH-Co interface leads to a limited stability and poor acidic OER due to Ir leaching. When doped into Co₃O₄ lattice, the analyses of X-ray absorption spectroscopy, in-situ Raman, and OER measurements show that the partially replacement of Co in Co₃O₄ by Ir atoms inclines to cause strong electronic effect and activate lattice oxygen in the presence of Ir-O-Co interface, and simultaneously master the reconstruction effect to mitigate Ir dissolution, realizing the improved OER activity and stability in alkaline and acidic environments. As a result, Ir_lat@Co₃O₄ with Ir loading of 3.67 wt% requires 294 ± 4 mV / 285 ± 3 mV and 326 ± 2 mV to deliver 10 mA cm⁻² in alkaline (0.1 M KOH / 1.0 M KOH) and acidic (0.5 M H₂SO₄) solution, respectively, with good stability.

CsPbI₂Br perovskite solar cells (PSCs) have drawn tremendous attention due to their suitable bandgap, excellent photothermal stability, and great potential as an ideal candidate for top cells in tandem solar cells. However, the abundant defects at the buried interface and perovskite layer induce severe charge recombination, resulting in the open-circuit voltage (V_oc) output and stability much lower than anticipated. Herein, a novel buried interface management strategy is developed to regulate interfacial carrier dynamics and CsPbI₂Br defects by introducing ammonium tetrafluoroborate (NH₄BF₄), thereby resulting in both high CsPbI₂Br crystallization and minimized interfacial energy losses. Specifically, NH₄⁺ ions could preferentially heal hydroxyl groups on the SnO₂ surface and balance energy level alignment between SnO₂ and CsPbI₂Br, enhancing charge transport efficiency, while BF₄⁻ anions as a quasi-halogen regulate crystal growth of CsPbI₂Br, thus reducing perovskite defects. Additionally, it is proved that eliminating hydroxyl groups at the buried interface enhances the iodide migration activation energy of CsPbI₂Br for strengthening the phase stability. As a result, the optimized CsPbI₂Br PSCs realize a remarkable efficiency of 17.09% and an ultrahigh V_oc output of 1.43 V, which is one of the highest values for CsPbI₂Br PSCs.

Lithium-sulfur battery (LSB) has brought much attention and concern because of high theoretical specific capacity and energy density as one of main competitors for next-generation energy storage systems. The widely commercial application and development of LSB is mainly hindered by serious “shuttle effect” of lithium polysulfides (LiPSs), slow reaction kinetics, notorious lithium dendrites, etc. In various structures of LSB materials, array structured materials, possessing the composition of ordered micro units with the same or similar characteristics of each unit, present excellent application potential for various secondary cells due to some merits such as immobilization of active substances, high specific surface area, appropriate pore sizes, easy modification of functional material surface, accommodated huge volume change, enough facilitated transportation for electrons/lithium ions, and special functional groups strongly adsorbing LiPSs. Thus many novel array structured materials are applied to battery for tackling thorny problems mentioned above. In this review, recent progresses and developments on array structured materials applied in LSBs including preparation ways, collaborative structural designs based on array structures, and action mechanism analyses in improving electrochemical performance and safety are summarized. Meanwhile, we also have detailed discussion for array structured materials in LSBs and constructed the structure-function relationships between array structured materials and battery performances. Lastly, some directions and prospects about preparation ways, functional modifications, and practical applications of array structured materials in LSBs are generalized. We hope the review can attract more researchers' attention and bring more studying on array structured materials for other secondary batteries including LSB.

For large-scale in-service electric vehicles (EVs) that undergo potential maintenance, second-hand transactions, and retirement, it is crucial to rapidly evaluate the health status of their battery packs. However, existing methods often rely on lengthy battery charging/discharging data or extensive training samples, which hinders their implementation in practical scenarios. To address this issue, a rapid health estimation method based on short-time charging data and limited labels for in-service battery packs is proposed in this paper. First, a digital twin of battery pack is established to emulate its dynamic behavior across various aging levels and inconsistency degrees. Then, increment capacity sequences (△Q) within a short voltage span are extracted from charging process to indicate battery health. Furthermore, data-driven models based on deep convolutional neural network (DCNN) are constructed to estimate battery state of health (SOH), where the synthetic data is employed to pre-train the models, and transfer learning strategies by using fine-tuning and domain adaptation are utilized to enhance the model adaptability. Finally, field data of 10 EVs exhibiting different SOHs are used to verify the proposed methods. By using the △Q with 100 mV voltage change, the SOH of battery packs can be accurately estimated with an error around 3.2%.

Despite the presence of LiF components in the solid electrolyte interphase (SEI) formed on the graphite anode surface by conventional electrolyte, these LiF components primarily exist in an amorphous state, rendering them incapable of effectively inhibiting the exchange reaction between lithium ions and transition metal ions in the electrolyte. Consequently, nearly all lithium ions within the SEI film are replaced by transition metal ions, resulting in an increase in interphacial impedance and a decrease in stability. Herein, we demonstrate that the SEI film, constructed by fluoroethylene carbonate (FEC) additive rich in crystalline LiF, effectively inhibits the undesired Li⁺/Co²⁺ ion exchange reaction, thereby suppressing the deposition of cobalt compounds and metallic cobalt. Furthermore, the deposited cobalt compounds exhibit enhanced structural stability and reduced catalytic activity with minimal impact on the interphacial stability of the graphite anode. Our findings reveal the crucial influence of SEI film composition and structure on the deposition and hazards associated with transition metal ions, providing valuable guidance for designing next-generation electrolytes.