RESUMEN

Zn anodes suffer from poor reversibility and stability owing to nonuniform dendrite growth and self-corrosion. Here, 1-ethyl-3-methylimidazolium acetate (EMImAc) is introduced to reconstruct interfacial electrical double layer with simultaneously manipulating the solvation environment and the adsorption situation on Zn anode. The acetate anions with high nucleophilicity can effectively alter the solvation shell around Zn2+ ions and immobilize the H2O molecules, thus weakening water activity and alleviating water-related parasitic reactions. Concomitantly, both the imidazolium cation and acetate anion are inclined to gather on Zn anode surface for constructing an electrostatic shielding layer, and meanwhile the chemisorbed acetate anions also contribute to accelerate the Zn(H2O)62+ desolvation process. Such a synergistic effect enables uniform electric field distribution and facilitates Zn ion flux, which mitigates the random diffusion of Zn2+ and finally promotes the dendrite-free deposition. As a result, the Zn/Zn symmetric cells with EMImAc-integrated aqueous electrolyte realize an excellent cycling lifespan of 7000 h (0.5 mA cm-2/0.25 mAh cm-2) and high Zn utilization of 61.3 % (15 mA cm-2/20 mAh cm-2). Furthermore, the effective of EMImAc additive is demonstrated in Zn/V2O5 cells. This work offers insights into the ionic liquid-integrated aqueous electrolytes to enhance the interface stability of Zn anode for rechargeable zinc batteries.

RESUMEN

Improving the wide-temperature operation of rechargeable batteries is crucial for boosting the adoption of electric vehicles and further advancing their application scope in harsh environments like deep ocean and space probes. Herein, recent advances in electrolyte solvation chemistry are critically summarized, aiming to address the long-standing challenge of notable energy diminution at sub-zero temperatures and rapid capacity degradation at elevated temperatures (>45°C). This review provides an in-depth analysis of the fundamental mechanisms governing the Li-ion transport process, illustrating how these insights have been effectively harnessed to synergize with high-capacity, high-rate electrodes. Another critical part highlights the interplay between solvation chemistry and interfacial reactions, as well as the stability of the resultant interphases, particularly in batteries employing ultrahigh-nickel layered oxides as cathodes and high-capacity Li/Si materials as anodes. The detailed examination reveals how these factors are pivotal in mitigating the rapid capacity fade, thereby ensuring a long cycle life, superior rate capability, and consistent high-/low-temperature performance. In the latter part, a comprehensive summary of in situ/operational analysis is presented. This holistic approach, encompassing innovative electrolyte design, interphase regulation, and advanced characterization, offers a comprehensive roadmap for advancing battery technology in extreme environmental conditions.

RESUMEN

Diluents have been extensively employed to overcome the disadvantages of high viscosity and sluggish kinetics of high-concentration electrolytes, but generally do not change the pristine solvation structure. Herein, a weakly coordinating diluent, hexafluoroisopropyl methyl ether (HFME), is applied to regulate the coordination of Na+ with diglyme and anion and form a diluent-participated solvate. This unique solvation structure promotes the accelerated decomposition of anions and diluents, with the construction of robust inorganic-rich electrode-electrolyte interphases. In addition, the introduction of HFME reduces the desolvation energy of Na+, improves ionic conductivity, strengthens the antioxidant, and enhances the safety of the electrolyte. As a result, the assembled Na||Na symmetric cell achieves a stable cycle of over 1800 h. The cell of Na||P'2-Na0.67MnO2 delivers a high capacity retention of 87.3 % with a high average Coulombic efficiency of 99.7 % after 350 cycles. This work provides valuable insights into solvation chemistry for advanced electrolyte engineering.

RESUMEN

High-performance sodium storage at low temperature is urgent with the increasingly stringent demand for energy storage systems. However, the aggravated capacity loss is induced by the sluggish interfacial kinetics, which originates from the interfacial Na+ desolvation. Herein, all-fluorinated anions with ultrahigh electron donicity, trifluoroacetate (TFA-), are introduced into the diglyme (G2)-based electrolyte for the anion-reinforced solvates in a wide temperature range. The unique solvation structure with TFA- anions and decreased G2 molecules occupying the inner sheath accelerates desolvation of Na+ to exhibit decreased desolvation energy from 4.16 to 3.49 kJ mol-1 and 24.74 to 16.55 kJ mol-1 beyond and below -20 °C, respectively, compared with that in 1.0 M NaPF6-G2. These enable the cell of Na||Na3V2(PO4)3 to deliver 60.2% of its room-temperature capacity and high capacity retention of 99.2% after 100 cycles at -40 °C. This work highlights regulation of solvation chemistry for highly stable sodium-ion batteries at low temperature.

RESUMEN

Herein, we optimize the primary solvation sheath to investigate the fundamental correlation between battery performance and electrode-electrolyte interfacial properties through electrolyte solvation chemistry. Experimental and theoretical analyses reveal that the primary solvation sheath with a self-purifying feature can "positively" scavenge both the HF and PF5 (hydrolysis of ion-paired LiPF6), stabilize the PF6 anion-derived electrode-electrolyte interfaces, and thus boost the cycling performances. Being attributed with these superiorities, the NCM811//Li Li metal battery (LMB) with the electrolyte containing the optimized solvation sheath delivers 99.9% capacity retention at 2.5 C after 250 cycles. To circumvent the impact of excess Li content of Li metal on the performance of NCM811 cathode, the as-fabricated NCM811//graphite Li ion battery (LIB) also delivers a high-capacity retention of 90.1% from the 5th to the 100th cycle at 1 C. This work sheds light on the strong ability of the primary solvation sheath to regulate cathode interfacial properties.

RESUMEN

Water-induced parasitic reactions and uncontrolled dendritic Zn growth are long-lasting tricky problems that severely hinder the development of aqueous zinc-metal batteries. Those notorious issues are closely related to electrolyte configuration and zinc-ion transport behavior. Herein, through constructing aligned dipoles induced electric-field on Zn surface, both the solvation structure and transport behavior of zinc-ions are fundamentally changed. The vertically ordered zinc-ion migration trajectory and gradually concentrated zinc-ion achieved inside the polarized electric-field remarkably eliminate water related side-reactions and Zn dendrites. Zn-metal under the polarized electric-field demonstrated significantly improve reversibility and a dendrite-free surface with strong (002) Zn deposition texturing. Zn||Zn symmetric cell delivers greatly prolonged lifespan up to 1400 h (17 times longer than that of the cell based on bare Zn) while the Zn||Cu half-cell demonstrate ultrahigh 99.9% coulombic efficiency. NH4 V4 O10 ||Zn half-cell delivered exceptional-high 132 mAh g-1 capacity after ultralong 2000 cycles (≈100% capacity retention). In addition, MnO2 ||Zn pouch-cell under aligned dipoles induced electric-field maintains 87.9% capacity retention after 150 cycles under practical condition of high MnO2 mass loading (≈10 mg cm-2 ) and limited N/P ratio. It is considered that this new strategy can also be implemented to other metallic batteries and spur the development of batteries with long-lifespan and high-energy-density.

RESUMEN

Advanced electrolyte design is essential for building high-energy-density lithium (Li) batteries, and introducing anions into the Li+ solvation sheaths has been widely demonstrated as a promising strategy. However, a fundamental understanding of the critical role of anions in such electrolytes is very lacking. Herein, the anionic chemistry in regulating the electrolyte structure and stability is probed by combining computational and experimental approaches. Based on a comprehensive analysis of the lowest unoccupied molecular orbitals, the solvents and anions in Li+ solvation sheaths exhibit enhanced and decreased reductive stability compared with free counterparts, respectively, which agrees with both calculated and experimental results of reduction potentials. Accordingly, new strategies are proposed to build stable electrolytes based on the established anionic chemistry. This work unveils the mysterious anionic chemistry in regulating the structure-function relationship of electrolytes and contributes to a rational design of advanced electrolytes for practical Li metal batteries.

RESUMEN

The performance of Li anodes is extremely affected by the solvation of Li ions, leading to preferential reduction of the solvation sheath and subsequent formation of fragile solid-electrolyte interphase (SEI), Li dendrites, and low coulombic efficiency (CE). Herein, we propose a novel strategy to regulate the solvation sheath, through the introduction of intermolecular hydrogen bonds with both the anions of Li salt and the solvent by small amount additives. The addition of such hydrogen bonds reduced the LUMO energy level of anions in electrolyte, promoted the formation of a robust SEI, reduced the amount of free solvent molecules, and enhanced stability of electrolytes. Based on this strategy, flat and dense lithium deposition was obtained. Even under lean electrolytes, at a current density of 1 mA cm-2 with a fixed capacity of 3 mAh cm-2 , the Li-Cu cells showed an impressive CE value of 99.2 %. The Li-LiFePO4 full cells showed long-term cycling stability for more than 1000 cycles at 1 C, with a total capacity loss of only 15 mAh g-1 .

RESUMEN

The low Coulombic efficiency of the lithium metal anode is recognized as the real bottleneck to practical high-efficiency lithium metal batteries with limited Li excess. The grain size and microstructure of deposited lithium strongly influences the lithium plating/stripping efficiency. Here, a solubilizer-mediated carbonate electrolyte that can realize grain coarsening of lithium deposits (>20 µm in width) with oriented columnar morphology, which is in sharp contrast with conventional nanoscale dendrite-like lithium deposits in carbonate electrolytes, is reported. It exhibits improved Li Coulombic efficiency to 98.14% at a high capacity of 3 mAh cm-2 over 150 cycles, because the colossal lithium deposition with minimal tortuosity can maintain the bulk Li with continuous electron conducting pathway during the stripping process, thus enabling efficient Li utilization. Li/NMC811 full batteries, composed of thin Li anode (45 µm) and a high-capacity NMC811 cathode (16.7 mg cm-2 ), can achieve at least 12 times longer lifespan (200 cycles).

RESUMEN

Szent-Gyorgi called water the "matrix of life" and claimed that there was no life without it. This statement is true, as far as we know, on our planet, but it is not clear whether it must hold throughout the cosmos. To evaluate that question requires a close consideration of the many varied and subtle roles that water plays in living cells-a consideration that must be free of both an assumed essentialism that gives water an almost mystical life-giving agency and a traditional tendency to see it as a merely passive solvent. Water is a participant in the "life of the cell," and here I describe some of the features of that active agency. Water's value for molecular biology comes from both the structural and dynamic characteristics of its status as a complex, structured liquid as well as its nature as a polar, protic, and amphoteric reagent. Any discussion of water as life's matrix must, however, begin with an acknowledgment that our understanding of it as both a liquid and a solvent is still incomplete.

Asunto(s)

Conformación Proteica , Agua/metabolismo , Animales , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Simulación de Dinámica Molecular , Agua/química

RESUMEN

We have incorporated the dye N-methyl-6-oxyquinolone [6MQz] in its protonated form as a cation into an ionic liquid (IL) and thus to synthesize an IL dye. The IL dye N-methyl-6-hydroxyquinolinium bis(trifluoromethylsulfonyl) imide [6MQc][NTf2 ] was characterized by NMR, ATR IR spectroscopy and X-ray crystallography. The fluorescence of the IL dye has a large Stokes shift of Δλ=116 nm and a quantum yield of φF =0.56 in acetonitrile. Characteristic solvent dependent shifts can be detected in the emission spectra. In other ILs, acetonitrile and THF we observe a bathochromic shift of up to 28 nm compared to the pure IL dye at 467 nm. For stronger polar solvents the fluorescence signals are strongly red-shifted to 650 nm indicating proton transfer to the solvent molecules in the excited state. This underlines the importance of the IL building block [MQc]+ as photo acid.

RESUMEN

Ionic liquids (ILs) attract interest in science and technology as a result of their unique properties. Binary and ternary mixtures of ILs significantly increase the number of possible cation/anion combinations, resulting in targeted physical and chemical properties. In this work, we study the mixing behaviour of two protic ILs: triethyl ammonium methylsulfonate [Et3 NH][CH3 SO3 ] and triethylammonium triflate [Et3 NH][CF3 SO3 ]. We find a characteristic deviation from ideal mixing by means of low-frequency infrared spectroscopy. By using molecular dynamics simulations, we explain this behaviour as being the result of different strengths of anion/cation hydrogen bonding. This non-ideality of non-random H-bond mixing is also reflected in macroscopic properties such as the viscosity. Mixing suitable ILs may, thus, result in new ILs with targeted physical properties.