Energy & Environmental Science最新文献

For LiCoO₂ (LCO) operating at high voltages (>4.5 V vs. Li/Li⁺), the intensive side reactions between LCO and traditional ethylene carbonate (EC)-based electrolytes with LiPF₆ salts can produce plenty of corrosive species (such as HF and HPO₂F₂), causing severe surface degradation. Herein, anti-oxidative fluoroethylene carbonate (FEC) and difluoroethylene carbonate (DFEC) were selected as co-solvents to reduce the generation of corrosive species. Besides, PF₆⁻ anions enrich the Helmholtz plane of the LCO/electrolyte interface and promote the formation of a robust cathode/electrolyte interphase (CEI) featuring LiF/Li_xPO_yF_z/Li₃PO₄ inorganics and P-containing organics under the synergy of fluorinated solvents, which significantly inhibits the catalysis of highly oxidative Co⁴⁺/Oⁿ⁻ (0 < n < 2). Benefiting from the reduced corrosive species and reinforced CEI, the layered structure of the LCO surface is well preserved during long-term cycling, with a highly reversible O3/H1-3 phase transition. Consequently, a LCO||graphite pouch cell exhibits a remarkable capacity retention of 85.7% after 500 cycles in 3.0–4.55 V. This work provides a new insight into developing advanced functional electrolytes for high-voltage lithium-ion batteries.

Garnet-type solid-state electrolytes (SSEs), typically Li_6.5La₃Zr_1.5Ta_0.5O₁₂ (LLZT), hold great promise for next-generation lithium metal batteries (LMBs). However, LLZT, with a high content of reactive Li⁺, is air-sensitive, which forms insulating and lithiophobic impurities, jeopardizing its practical applications. Here, we demonstrate that crust-localized Fe³⁺ doping of the LLZT pellet (CF-LLZT) ensures high air stability and lithium compatibility without hurting its ionic conductivity. Briefly, Fe₂O₃ nanofilms are first deposited onto the LLZT substrate, and subsequent high-temperature sintering drives Fe³⁺ into the underneath LLZT, forming a Li⁺ deficient crust with the bulk structure unchanged. This surface-renovated LLZT can extend air-exposure time up to 1 month without forming Li₂CO₃ containments. The symmetric cell of Li/CF-LLZT/Li shows a low interfacial resistance of 6 Ω cm² (1580 Ω cm² for Li/LLZT/Li) and stable electrochemical performance (>5000 h). The assembled LMBs using different cathode materials, particularly LiFePO₄ and LiNi_0.83Co_0.07Mn_0.1O₂, demonstrate high reversible capacity and promising cycling capability. Unlike bulk Fe³⁺ doping, which results in a significant decline in Li⁺ conductivity and renders it unsuitable for use in SSEs, our study highlighted the importance of surface structure modulation of SSEs as an effective research avenue to circumvent the interfacial challenge to facilitate their future commercialization.

Na-ion batteries (NIBs) are emerging as a promising alternative to Li-ion batteries (LIBs). To align with sustainability principles, the design of electrode materials must incorporate considerations for abundant and environmentally friendly elements, such as redox-active Fe. Despite its appeal, the enduring challenge of Fe migration in layered cathodes remains inadequately addressed over decades. Here, we propose a “seat-squatting” strategy via Li-substitution to fundamentally suppress Fe migration. Li is strategically introduced to migrate first, occupying available migration sites without inducing structural damage and effectively raising the activation energy for Fe migration. Experimental and theoretical validation using O3-Na_0.83Li_0.17Fe_0.33Mn_0.5O₂ (NaLFM) demonstrates a robust suppression of irreversible Fe migration. As a result, the NaLFM cathode delivers enhanced structural and electrochemical cycling stability. This work illustrates a compelling strategy to curb irreversible Fe migration in NIBs, offering a pathway for the development of stable and cost-effective layered oxides based on Fe redox centers.

Zn-ion batteries (ZIBs) are considered as a viable candidate for grid-scale energy storage with admirable capacity, high safety and low cost, but are severely hampered by the undesirable dendrite growth and parasitic reactions at the Zn anode side. The compositions of the electrolytes are critical to the performance enhancement of ZIBs. Conventional electrolytes are unable to meet the ever-growing requirements for fast-charging and wide-temperature operation of ZIBs. Despite the great achievements of (localized) highly concentrated electrolytes and low concentrated electrolytes with high donor number additives, they still face challenges of low ionic conductivity, high cost and sluggish de-solvation kinetics of Zn²⁺. Therefore, weakly solvating electrolytes (WSEs) are proposed to improve the aforementioned shortcomings, which have attracted intensive research enthusiasm in recent years. This review analyzes the functions, design criteria, and recent progress of WSEs and then a vision on future directions in this field is also presented. The insights will benefit the development of next-generation high-performance ZIBs.

Lithium–sulfur (Li–S) batteries are deemed one of the most promising high-energy density battery technologies. However, their operation under thermal extremes, e.g., subzero and above 60 °C, remains largely underexplored. Especially, high temperatures (HT) accelerate sulfur dissolution and undesired side reactions, presenting significant challenges for electrolyte design. In this work, contrary to traditional understanding, we discovered that even (localized) high-concentration electrolytes (HCEs), which have shown promise within moderate temperature ranges (0–60 °C), fail at temperatures above 80 °C. Detailed investigations revealed that Li-anion aggregates in HCE trigger uncontrolled reductive decomposition at the Li anode side once the temperature exceeds a threshold of 80 °C. The resultant parasitic byproducts caused serious crosstalk and cathode oxidation in HT Li–S batteries. To counter this issue, we developed a localized medium-concentration electrolyte that features a well-mediated solvation structure and energy level, demonstrating excellent thermodynamic stability at high temperatures with superb kinetics at low temperatures. Consequently, high-performance and safely operating Li–S pouch cells are achieved over an unprecedented range of −20 to 100 °C. These findings link electrolyte microstructure, temperature, SEI structure, and degradation mechanism, offering a design protocol for the reliable function of batteries in extreme environments.

Direct oxidation of methane (DOM) using molecular oxygen (O₂) and hydrogen (H₂) is currently considered to be triggered by in situ produced H₂O₂ or free hydroxyl radicals (˙OH). However, the role of the surface hydroxyl group in the DOM that is in situ formed from O₂ and H₂ has long been ignored. Herein, we provide experimental evidence that DOM using H₂ and O₂ over titanium silicate-supported single Pd atoms coated with an ultrathin N-doped carbon (Pd₁/TS-1@CN) catalyst is dominated by a surface hydroxyl group instead of H₂O₂ or free ˙OH. Furthermore, the direct bonding between Pd atoms with the pyrrolic nitrogen of the coating layers reinforces the bonding strength of Pd₁ and framework oxygen, forming a unique N₁–Pd₁–O₂ configuration that considerably boosts the stability of isolated Pd active sites and their capability to stably generate a surface hydroxyl group from H₂ and O₂. Therefore, Pd₁/TS-1@CN yields a liquid oxygenate productivity of 647 μmol g_cat⁻¹ h⁻¹ with 100% selectivity at 15 °C and high stability over 30 cycles with no activity loss. Our findings regarding the catalytic role of the surface hydroxyl group in DOM and its stabilization strategy open up a new avenue for designing advanced catalysts for the DOM using O₂ under mild reaction conditions.

The crystalline phases of solid-state polymer electrolytes (SPEs) are commonly believed to be ionic insulators. Herein, we show that contrary to this prevailing view, lithium ions (Li⁺) can be transported in crystalline phases of poly(vinylidene fluoride) (PVDF) after incorporating dipolar defects into crystals. By increasing the interchain distance, these defects enable an easy flipping and vibrating of –CH₂CF₂ dipoles, which triggers a rapid motion of Li⁺ in crystals through ion–dipole interactions. Such an unexpected transformation from ion-insulated crystals to ion-conductive and defective crystals endowed a PVDF-based SPE with an extremely high ionic conductivity of 7.8 × 10⁻⁴ S cm⁻¹ at 25 °C. The developed SPE showed a high stability with both lithium metal anodes and high-voltage cathodes. In particular, solid-state Li//Li symmetrical cells could cycle for more than 11 000 h (>450 days) at room temperature. Moreover, the solid-state full cell can rapidly charge at 5C (12 min) with a capacity retention of around 100% after 400 cycles at 25 °C. This work paves a new way to improve ionic conductivities of SPEs and realize the fast charging of solid-state lithium metal batteries (LMBs) by including dipolar defects to convert ion-insulated crystals into fast ionic conductors.

Lactic acid is commonly used as a sacrificial agent while neglecting its prospects for value-added chemical conversion due to inefficient hole utilization of the photocatalyst. In the present study, we demonstrate a strategy of anchoring atomic-level Pd on CdS_x twins to maximize the utilization of electrons and holes for efficient photocatalytic hydrogen evolution coupled with pyruvate synthesis. The Pd-CdS_x-Twins photocatalyst achieved a remarkable H₂ evolution rate of 7700.25 μmol h⁻¹ with a disruptive apparent quantum efficiency of 90.2% and pyruvic acid production with a selectivity of 95.87%. The back-to-back barrier field induced by the CdS_x twins served as the prerequisite for the surface enrichment and isolated extraction of the photocarriers. TA spectroscopy, in situ XPS, and theoretical calculations proved that the Pd single atoms stabilize the twin crystal structure and provides optimal conditions for the adsorption of lactic acid molecules while promoting the extraction of holes, while the surface-enriched electrons at the S site promote hydrogen extraction. This study developed an attractive route for the utilization of photocarriers simultaneously at the reducing and oxidizing sides while expanding the economic benefits of traditional hole-sacrificial systems.

Achieving near-zero overpotential for a large-scale hydrogen evolution reaction (HER) using multi-principal element alloys is a formidable challenge. These alloys, characterized by their diverse compositions and complex atomic configurations, offer a broad spectrum of catalytic sites, positioning them as candidates of interest in energy and environmental applications. However, conventional methods for improving the catalytic performance of these alloys, which focus on element composition and the cocktail effect, frequently undervalue the role of structural design. In this work, we introduce an innovative approach that integrates oxygen incorporation with dual-phase supra-nanostructuring to boost the catalytic efficacy of a multi-principal element alloy via industrial magnetron sputtering at ambient temperature. Specifically, the oxygen-incorporated crystal-amorphous dual-phase supra-nanostructured palladium/multi-principal element alloy (denoted as SNDP-Pd@HEAA) presents a plethora of uniformly distributed interfaces enriched with unique next-nearest oxygen-coordinated active sites, which contribute to its exceptional HER performance. The SNDP-Pd@HEAA exhibits a near zero overpotential of 10.16 mV at a current density of 10 mA cm⁻², which is much lower than that of 34.01 mV of commercial 20% Pt/C. Remarkably, it retains a reliable long-term stability of ∼1000 h at 500 mA cm⁻² in an anion exchange membrane (AEM) device, which is significantly higher than that of the reported commercial Pt/C||IrO₂ system. The structural and computational results reveal that the SNDP-Pd@HEAA comprising Pd-rich nanocrystalline cores and O-rich amorphous glassy shells produces plentiful active interfaces and special active Pd sites with next-nearest O coordination, thus actively promoting water adsorption capacity and accelerating hydrogen proton adsorption/desorption. This SNDP nanostructure production and oxygen-incorporated manipulation technique, as well as the next-nearest O-coordinated active sites mechanism, establishes a new paradigm for hydrogen evolution reaction catalysts.