能源化学最新文献

Advancing high-voltage stability of layered sodium-ion oxides represents a pivotal avenue for their progress in energy storage applications. Despite this, a comprehensive understanding of the mechanisms underpinning their structural deterioration at elevated voltages remains insufficiently explored. In this study, we unveil a layer delamination phenomenon of Na_0.67Ni_0.3Mn_0.7O₂ (NNM) within the 2.0–4.3 V voltage, attributed to considerable volumetric fluctuations along the c-axis and lattice oxygen reactions induced by the simultaneous Ni³⁺/Ni⁴⁺ and anion redox reactions. By introducing Mg doping to diminished Ni–O antibonding, the anion oxidation-reduction reactions are effectively mitigated, and the structural integrity of the P2 phase remains firmly intact, safeguarding active sites and precluding the formation of novel interfaces. The Na_0.67Mg_0.05Ni_0.25Mn_0.7O₂ (NMNM-5) exhibits a specific capacity of 100.7 mA h g⁻¹, signifying an 83% improvement compared to the NNM material within the voltage of 2.0–4.3 V. This investigation underscores the intricate interplay between high-voltage stability and structural degradation mechanisms in layered sodium-ion oxides.

Polymer-based composite electrolytes composed of three-dimensional Li_6.4La₃Zr₂Al_0.2O₁₂ (3D-LLZAO) have attracted increasing attention due to their continuous ion conduction and satisfactory mechanical properties. However, the organic/inorganic interface is incompatible, resulting in slow lithium-ion transport at the interface. Therefore, the compatibility of organic/inorganic interface is an urgent problem to be solved. Inspired by the concept of “gecko eaves”, polymer-based composite solid electrolytes with dense interface structures were designed. The bridging of organic/inorganic interfaces was established by introducing silane coupling agent (3-chloropropyl)trimethoxysilane (CTMS) into the PEO-3D-LLZAO (PL) electrolyte. The in-situ coupling reaction improves the interface affinity, strengthens the organic/inorganic interaction, reduces the interface resistance, and thus achieves an efficient interface ion transport network. The prepared PEO-3D-LLZAO-CTMS (PLC) electrolyte exhibits enhanced ionic conductivity of 6.04 × 10⁻⁴ S cm⁻¹ and high ion migration number (0.61) at 60 °C and broadens the electrochemical window (5.1 V). At the same time, the PLC electrolyte has good thermal stability and high mechanical properties. Moreover, the LiFePO₄|PLC|Li battery has excellent rate performance and cycling stability with a capacity decay rate of 2.2% after 100 cycles at 60 °C and 0.1 C. These advantages of PLC membranes indicate that this design approach is indeed practical, and the in-situ coupling method provides a new approach to address interface compatibility issues.

The anti-freezing strategy of hydrogels and their self-healing structure are often contradictory, it is vital to break through the molecular structure to design and construct hydrogels with intrinsic anti-freezing/self-healing for meeting the rapid development of flexible and wearable devices in diverse service conditions. Herein, we design a new hydrogel electrolyte (AF/SH-Hydrogel) with intrinsic anti-freezing/self-healing capabilities by introducing ethylene glycol molecules, dynamic chemical bonding (disulfide bond), and supramolecular interaction (multi-hydrogen bond) into the polyacrylamide molecular chain. Thanks to the exceptional freeze resistance (84% capacity retention at −20 °C) and intrinsic self-healing capabilities (95% capacity retention after 5 cutting/self-healing cycles), the obtained AF/SH-Hydrogel makes the zinc||manganese dioxide cell an economically feasible battery for the state-of-the-art applications. The Zn||AF/SH-Hydrogel||MnO₂ device offers a near-theoretical specific capacity of 285 mA h g⁻¹ at 0.1 A g⁻¹ (Coulombic efficiency ≈100%), as well as good self-healing capability and mechanical flexibility in an ice bath. This work provides insight that can be utilized to develop multifunctional hydrogel electrolytes for application in next generation of self-healable and freeze-resistance smart aqueous energy storage devices.

The d-d orbital coupling induced by crystal-phase engineering can effectively adjust the electronic structure of electrocatalysts, thus showing significant catalytic performance, while it has been rarely explored in electrochemical acetonitrile reduction reaction (ARR) to date. Herein, we successfully realize the structural transformation of PdCu metallic aerogels (MAs) from face-centered cubic (FCC) to body-centered cubic (BCC) through annealing treatment. Specifically, the BCC PdCu MAs exhibit excellent ARR performance with high ethylamine selectivity of 90.91%, Faradaic efficiency of 88.60%, yield rate of 316.0 mmol h⁻¹ g⁻¹_Pd+Cu and long-term stability for consecutive electrolysis within 20 h at −0.55 V vs. reversible hydrogen electrode, outperforming than those of FCC PdCu MAs. Under the membrane electrode assembly system, BCC PdCu MAs also demonstrate excellent ethylamine yield rate of 389.5 mmol h⁻¹ g⁻¹_Pd+Cu. Density functional theory calculation reveals that the d-d orbital coupling in BCC PdCu MAs results in an evident correlation effect for the interaction of Pd and Cu sites, which boosts up the Cu sites electronic activities to enhance ARR performance. Our work opens a new route to develop efficient ARR electrocatalysts from the perspective of crystalline structure transformation.

Exploration of advanced gel polymer electrolytes (GPEs) represents a viable strategy for mitigating dendritic lithium (Li) growth, which is crucial in ensuring the safe operation of high energy density Li metal batteries (LMBs). Despite this, the application of GPEs is still hindered by inadequate ionic conductivity, low Li⁺ transference number, and subpar physicochemical properties. Herein, TiO_2−x nanofibers (NF) with oxygen vacancy defects were synthesized by a one-step process as inorganic fillers to enhance the thermal/mechanical/ionic-transportation performances of composite GPEs. Various characterizations and theoretical calculations reveal that the oxygen vacancies on the surface of TiO_2−x NF accelerate the dissociation of LiPF₆, promote the rapid transfer of free Li⁺, and influence the formation of LiF-enriched solid electrolyte interphase. Consequently, the composite GPEs demonstrate enhanced ionic conductivity (1.90 mS cm⁻¹ at room temperature), higher lithium-ion transference number (0.70), wider electrochemical stability window (5.50 V), superior mechanical strength, excellent thermal stability (210 °C), and improved compatibility with lithium, resulting in superior cycling stability and rate performance in both Li||Li, Li||LiFePO₄, and Li||LiNi_0.8Co_0.1Mn_0.1O₂ cells. Overall, the synergistic influence of nanofiber morphology and enriched oxygen vacancy structure of fillers on electrochemical properties of composite GPEs is comprehensively investigated, thus, it is anticipated to shed new light on designing high-performance GPEs LMBs.

Electrocatalytic overall water splitting (OWS), a pivotal approach in addressing the global energy crisis, aims to produce hydrogen and oxygen. However, most of the catalysts in powder form are adhesively bounding to the electrodes, resulting in catalyst detachment by bubble generation and other uncertain interference, and eventually reducing the OWS performance. To surmount this challenge, we synthesized a hybrid material of Co₃S₄- pyrolysis lotus fiber (labeled as Co₃S₄-pLF) textile by hydrothermal and high-temperature pyrolysis processes for electrocatalytic OWS. Owing to the natural LF textile exposing the uniformly distributed functional groups (OH, NH₂, etc.) to anchor Co₃S₄ nanoparticles with hierarchical porous structure and outstanding hydrophily, the hybrid Co₃S₄-pLF catalyst shows low overpotentials at 10 mA cm⁻² (η_{10, HER} = 100 mV η_{10, OER} = 240 mV) alongside prolonged operational stability during electrocatalytic reactions. Theoretical calculations reveal that the electron transfer from pLF to Co₃S₄ in the hybrid Co₃S₄-pLF is beneficial to the electrocatalytic process. This work will shed light on the development of nature-inspired carbon-based materials in hybrid electrocatalysts for OWS.

Safe batteries are the basis for next-generation application scenarios such as portable energy storage devices and electric vehicles, which are crucial to achieving carbon neutralization. Electrolytes, separators, and electrodes as main components of lithium batteries strongly affect the occurrence of safety accidents. Responsive materials, which can respond to external stimuli or environmental change, have triggered extensive attentions recently, holding great promise in facilitating safe and smart batteries. This review thoroughly discusses recent advances regarding the construction of high-safety lithium batteries based on internal thermal-responsive strategies, together with the corresponding changes in electrochemical performance under external stimulus. Furthermore, the existing challenges and outlook for the design of safe batteries are presented, creating valuable insights and proposing directions for the practical implementation of safe lithium batteries.

Vanadium-based electrodes are regarded as attractive cathode materials in aqueous zinc ion batteries (ZIBs) caused by their high capacity and unique layered structure. However, it is extremely challenging to acquire high electrochemical performance owing to the limited electronic conductivity, sluggish ion kinetics, and severe volume expansion during the insertion/extraction process of Zn²⁺. Herein, a series of V₂O₃ nanospheres embedded N-doped carbon nanofiber structures with various V₂O₃ spherical morphologies (solid, core–shell, hollow) have been designed for the first time by an electrospinning technique followed thermal treatments. The N-doped carbon nanofibers not only improve the electrical conductivity and the structural stability, but also provides encapsulating shells to prevent the vanadium dissolution and aggregation of V₂O₃ particles. Furthermore, the varied morphological structures of V₂O₃ with abundant oxygen vacancies can alleviate the volume change and increase the Zn²⁺ pathway. Besides, the phase transition between V₂O₃ and Zn_XV₂O_5−m·nH₂O in the cycling was also certified. As a result, the as-obtained composite delivers excellent long-term cycle stability and enhanced rate performance for coin cells, which is also confirmed through density functional theory (DFT) calculations. Even assembled into flexible ZIBs, the sample still exhibits superior electrochemical performance, which may afford new design concept for flexible cathode materials of ZIBs.

In this study, we systematically investigated the effect of proton concentration on the kinetics of the oxygen reduction reaction (ORR) on Pt(111) in acidic solutions. Experimental results demonstrate a rectangular hyperbolic relationship, i.e., the ORR current excluding the effect of other variables increases with proton concentration and then tends to a constant value. We consider that this is caused by the limitation of ORR kinetics by the trace oxygen concentration in the solution, which determines the upper limit of ORR kinetics. A model of effective concentration is further proposed for rectangular hyperbolic relationships: when the reactant concentration is high enough to reach a critical saturation concentration, the effective reactant concentration will become a constant value. This could be due to the limited concentration of a certain reactant for reactions involving more than one reactant or the limited number of active sites available on the catalyst. Our study provides new insights into the kinetics of electrocatalytic reactions, and it is important for the proper evaluation of catalyst activity and the study of structure-performance relationships.

The recycling and reutilization of spent lithium-ion batteries (LIBs) have become an important measure to alleviate problems like resource scarcity and environmental pollution. Although some progress has been made, battery recycling technology still faces challenges in terms of efficiency, effectiveness and environmental sustainability. This review aims to systematically review and analyze the current status of spent LIB recycling, and conduct a detailed comparison and evaluation of different recycling processes. In addition, this review introduces emerging recycling techniques, including deep eutectic solvents, molten salt roasting, and direct regeneration, with the intent of enhancing recycling efficiency and diminishing environmental repercussions. Furthermore, to increase the added value of recycled materials, this review proposes the concept of upgrading recycled materials into high value-added functional materials, such as catalysts, adsorbents, and graphene. Through life cycle assessment, the paper also explores the economic and environmental impacts of current battery recycling and highlights the importance that future recycling technologies should achieve a balance between recycling efficiency, economics and environmental benefits. Finally, this review outlines the opportunities and challenges of recycling key materials for next-generation batteries, and proposes relevant policy recommendations to promote the green and sustainable development of batteries, circular economy, and ecological civilization.