能源化学最新文献

Li metal batteries using high-voltage layered oxides cathodes are of particular interest due to their high energy density. However, they suffer from short lifespan and extreme safety concerns, which are attributed to the degradation of layered oxides and the decomposition of electrolyte at high voltage, as well as the high reactivity of metallic Li. The key is the development of stable electrolytes against both high-voltage cathodes and Li with the formation of robust interphase films on the surfaces. Herein, we report a highly fluorinated ether, 1,1,1-trifluoro-2-[(2,2,2-trifluoroethoxy) methoxy] ethane (TTME), as a co-solvent, which not only functions as a diluent forming a localized high concentration electrolyte (LHCE), but also participates in the construction of the inner solvation structure. The TTME-based electrolyte is stable itself at high voltage and induces the formation of a unique double-layer solid electrolyte interphase (SEI) film, which is embodied as one layer rich in crystalline structural components for enhanced mechanical strength and another amorphous layer with a higher concentration of organic components for enhanced flexibility. The Li||Cu cells display a noticeably high Coulombic efficiency of 99.28% after 300 cycles and Li symmetric cells maintain stable cycling more than 3200 h at 0.5 mA/cm² and 1.0 mAh/cm². In addition, lithium metal cells using LiNi_0.8Co_0.1Mn_0.1O₂ and LiCoO₂ cathodes (both loadings ∼3.0 mAh/cm²) realize capacity retentions of >85% over 240 cycles with a charge cut-off voltage of 4.4 V and 90% for 170 cycles with a charge cut-off voltage of 4.5 V, respectively. This study offers a bifunctional ether-based electrolyte solvent beneficial for high-voltage Li metal batteries.

The reliable prediction of state of charge (SOC) is one of the vital functions of advanced battery management system (BMS), which has great significance towards safe operation of electric vehicles. By far, the empirical model-based and data-driven-based SOC estimation methods of lithium-ion batteries have been comprehensively discussed and reviewed in various literatures. However, few reviews involving SOC estimation focused on electrochemical mechanism, which gives physical explanations to SOC and becomes most attractive candidate for advanced BMS. For this reason, this paper comprehensively surveys on physics-based SOC algorithms applied in advanced BMS. First, the research progresses of physical SOC estimation methods for lithium-ion batteries are thoroughly discussed and corresponding evaluation criteria are carefully elaborated. Second, future perspectives of the current researches on physics-based battery SOC estimation are presented. The insights stated in this paper are expected to catalyze the development and application of the physics-based advanced BMS algorithms.

Lithium recovery from end-of-life Li-ion batteries (LIBs) through pyro- and hydrometallurgical recycling processes involves several refining stages, with high consumption of reagents and energy. A competitive technological alternative is the electrochemical oxidation of the cathode materials, whereby lithium can be deintercalated and transferred to an electrolyte solution without the aid of chemical extracting compounds. This article investigates the potential to selectively recover Li from LIB cathode materials by direct electrochemical extraction in aqueous solutions. The process allowed to recovering up to 98% of Li from high-purity commercial cathode materials (LiMn₂O₄, LiCoO₂, and LiNi_1/3Mn_1/3Co_1/3O₂) with a faradaic efficiency of 98% and negligible co-extraction of Co, Ni, and Mn. The process was then applied to recover Li from the real waste LIBs black mass obtained by the physical treatment of electric vehicle battery packs. This black mass contained graphite, conductive carbon, and metal impurities from current collectors and steel cases, which significantly influenced the evolution and performances of Li electrochemical extraction. Particularly, due to concomitant oxidation of impurities, lithium extraction yields and faradaic efficiencies were lower than those obtained with high-purity cathode materials. Copper oxidation was found to occur within the voltage range investigated, but it could not quantitatively explain the reduced Li extraction performances. In fact, a detailed investigation revealed that above 1.3 V vs. Ag/AgCl, conductive carbon can be oxidized, contributing to the decreased Li extraction. Based on the reported experimental results, guidelines were provided that quantitatively enable the extraction of Li from the black mass, while preventing the simultaneous oxidation of impurities and, consequently, reducing the energy consumption of the proposed Li recovery method.

Due to its low cost and natural abundance of sodium, Na-ion batteries (NIBs) are promising candidates for large-scale energy storage systems. The development of ultralow voltage anode materials is of great significance in improving the energy density of NIBs. Low-voltage anode materials, however, are severely lacking in NIBs. Of all the reported insertion oxides anodes, the Na₂Ti₃O₇ has the lowest operating voltage (an average potential of 0.3 V vs. Na⁺/Na) and is less likely to deposit sodium, which has excellent potential for achieving NIBs with high energy densities and high safety. Although significant progress has been made, achieving Na₂Ti₃O₇ electrodes with excellent performance remains a severe challenge. This paper systematically summarizes and discusses the physicochemical properties and synthesis methods of Na₂Ti₃O₇. Then, the sodium storage mechanisms, key issues and challenges, and the optimization strategies for the electrochemical performance of Na₂Ti₃O₇ are classified and further elaborated. Finally, remaining challenges and future research directions on the Na₂Ti₃O₇ anode are highlighted. This review offers insights into the design of high-energy and high-safety NIBs.

This study investigates the effects of Fe on the oxygen-evolution reaction (OER) in the presence of Au. Two distinct areas of OER were identified: the first associated with Fe sites at low overpotential (≈330 mV), and the second with Au sites at high overpotential (≈870 mV). Various factors such as surface Fe concentration, electrochemical method, scan rate, potential range, concentration, method of adding K₂FeO₄, nature of Fe, and temperature were varied to observe diverse behaviors during OER for FeO_xH_y/Au. Trace amounts of Fe ions had a significant impact on OER, reaching a saturation point where the activity did not increase further. Strong electronic interaction between Fe and Au ions was indicated by X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) analyses. In situ visible spectroscopy confirmed the formation of FeO₄²⁻ during OER. In situ Mössbauer and surface-enhanced Raman spectroscopy (SERS) analyses suggest the involvement of Fe-based species as intermediates during the rate-determining step of OER. A lattice OER mechanism based on FeO_xH_y was proposed for operation at low overpotentials. Density functional theory (DFT) calculations revealed that Fe oxide, Fe-oxide clusters, and Fe doping on the Au foil exhibited different activities and stabilities during OER. The study provides insights into the interplay between Fe and Au in OER, advancing the understanding of OER mechanisms and offering implications for the design of efficient electrocatalytic systems.

Phenazine-based non-fullerene acceptors (NFAs) have demonstrated great potential in improving the power conversion efficiency (PCE) of organic solar cells (OSCs). Halogenation is known to be an effective strategy for increasing optical absorption, refining energy levels, and improving molecular packing in organic semiconductors. Herein, a series of NFAs (PzIC-4H, PzIC-4F, PzIC-4Cl, PzIC-2Br) with phenazine as the central core and with/without halogen-substituted (dicyanomethylidene)-indan-1-one (IC) as the electron-accepting end group were synthesized, and the effect of end group matched phenazine central unit on the photovoltaic performance was systematically studied. Synergetic photophysical and morphological analyses revealed that the PM6:PzIC-4F blend involves efficient exciton dissociation, higher charge collection and transfer rates, better crystallinity, and optimal phase separation. Therefore, OSCs based on PM6:PzIC-4F as the active layer exhibited a PCE of 16.48% with an open circuit voltage (V_oc) and energy loss of 0.880 V and 0.53 eV, respectively. Accordingly, this work demonstrated a promising approach by designing phenazine-based NFAs for achieving high-performance OSCs.