Ethylene Carbonate Research Articles

New Discovery of Diethyl Carbonate Modified Natural Hydraulic Lime in Heritage Conservation

ABSTRACT Cracks are one of the common diseases on the surface and inside of stone cultural relics. The research and application of grouting materials are crucial for crack conservation of cultural relics. This work mainly studies the modification of Natural Hydraulic Lime (NHL2), a commonly used crack grouting material for stone cultural relics. Diethyl Carbonate (DEC) is used to modify Natural Hydraulic Lime to provide a carbon source within the system, and it can produce the raw material (CO2) needed for the reaction to maintain the continuous occurrence of hydration and carbonation reactions. Diethyl Carbonate-modified Natural Hydraulic Lime (DEC-NHL2) can keep the original physical phase and composition unchanged, refine the grain size, and increase the product of the hydration and carbonation reaction. In addition, it can promote the synchronous carbonation of the inner and surface parts, accelerate the coagulation rate of the slurry and improve the compressive strength, thus substantially enhancing the reaction continuity and stability of the NHL2 slurry, and avoiding the repair damage caused by stress concentration. It provides a new idea for grouting and protection of stone cultural heritages.

–C≡N functionalizing polycarbonate-based solid-state polymer electrolyte compatible to high-voltage cathodes

Solid-state polymer electrolytes (SPEs) capable of withstanding high voltage are considered to be key for next-generation energy storage devices with inherent safety as well as high energy density. This study involves the rational design of solid-state –C≡N functionalized P(VEC1-CEA0.3)/LiTFSI@CE SPEs and its synthesis by in-situ free radical polymerization of vinyl ethylene carbonate (VEC) and 2-cyanoethyl acrylate (CEA). In situ polymerization yields electrode/electrolyte interfaces with low interfacial resistance, forming a stable SEI layer enriched with LiF, Li3N, and RCOOLi, ensuring stable Li plating/stripping for over 1400 h. The –C≡N moiety renders the αH on the adjacent αC positively charged, thereby endowing it with the capability to anchor TFSI−. Simultaneously, the incorporation of –C≡N moiety diminishes the electron-donating ability of the C = O, C–O–C, and –C≡N functional groups, facilitating not only the ion conductivity enhancement but also a more rapid Li+ migration proved by DFT theoretical calculations and Raman spectroscopy. At room temperature, tLi+ of 0.60 for P(VEC1-CEA0.3)/LiTFSI@CE SPEs is achieved when the ionic conductivity σLi+ is 2.63 × 10−4 S cm−1 and the electrochemical window is expanded to 5.0 V. Both coin cells with high-areal-loading cathodes and the 6.5-mAh pouch cell, exhibit stable charge/discharge cycling. At 25 °C, the 4.45-V Li|P(VEC1-CEA0.3)/LiTFSI@CE|LiCoO2 battery performs stable cycling over 200 cycles at 0.2 C, with a capacity retention of 82.1%.

Revisit coupling of CO2 to ethylene carbonate with an integrated imidazolium and zinc halides catalyst by a study on its decomposition: Active center and mechanism

Coupling of carbon dioxide (CO2) to cyclic carbonates with an epoxide and further into linear carbonates as the indispensable solvents for the lithium-ion batteries has been being one of the hottest topics in transforming CO2 into high value-added chemicals. Nevertheless, the extremely ultrahigh purity requirement for them causes a low efficiency and a modest yield due to the undesired reactions and byproducts occurring in the separation and purification sections. In this work, a novel imidazolium based ionic liquid catalyst system with different anions and cations was studied by a thorough insight into the decomposition reaction of ethylene carbonate (EC), which reveals the synergistic mechanism of the composite catalysts both in section of cyclic carbonate separation from the catalyst for recirculated utilization and purification from the byproducts, and in section of synthesis with high efficiency. Effects of imidazolium cations and halogen anions in the ionic liquid molecule on EC decomposition were investigated by the elaborately designed experiments, thermodynamic estimations, molecular dynamics simulation and DFT assessment. It was found that combining imidazole salts and zinc halides can greatly boost the activity of EC synthesis and decomposition with the effective structure of catalytic center being [EMIm]ZnX4. Furthermore, it was indicated that Br- has a higher activity for EC synthesis and its reversed pyrolysis, while Cl- will promote a side reaction of ring-opening polymerization of EC. Finally, a most favorable catalyst composition with ZnBr2 and [EMIm]Br for EC synthesis was achieved with a high efficiency in synthesis and a low tendency to initiate the side reactions in separation section.

Zirconium Catalyst Grafted on Ceria‐Coated Silica for Transformation of Carbon Dioxide to Diethyl Carbonate

Zirconium Catalyst Grafted on Ceria‐Coated Silica for Transformation of Carbon Dioxide to Diethyl Carbonate

Low-temperature fabrication of lead-free Ag2BiI5 perovskite photodetector with excellent weak light detection ability for accurate gesture recognition

In recent years, lead halide perovskites have been extensively researched in the optoelectronics field due to their excellent optical and electrical properties, while the inherent toxicity and instability of lead halide perovskites have hindered their commercialization. Stable, lead-free perovskites as a substitute of the Pb-based perovskites show great attention. Herein, the green antisolvent diethyl carbonate is introduced to realize the low-temperature fabrication of nontoxic perovskite Ag2BiI5. The Ag2BiI5 perovskite photodetector (PD) shows excellent performance with a detectivity of as high as 1.13 × 1013 Jones and a linear dynamic range (LDR) of 147 dB. Besides, the weak light with the light intensity of as low as 18.3 nW/cm2 can be detected by our PD. Moreover, the flexible PDs are also prepared with this low-temperature process, which shows good device performance with stable bending resistance characteristics. Based on the excellent optoelectronic properties of the Ag2BiI5 PDs, a gesture recognition system is built which can realize rapid and accurate gesture recognition under ordinary indoor light, with an accuracy of 98.35 %. Our research provides new insights for the development and application of green and environmentally friendly perovskite PD.

Unlocking the Use of LiCl as an Inexpensive Salt for Lithium-Ion Batteries with a Novel Anion Receptor.

Lithium chloride (LiCl) is an inexpensive and environmentally friendly salt abundant in the ocean. However, the insolubility of LiCl in conventional electrolyte solvents prevents the practical use of LiCl for lithium-ion batteries. Here, we report a novel method to increase the solubility of LiCl in a conventional electrolyte. The solubility of LiCl in ethylene carbonate (EC)/dimethyl carbonate (DMC) (1/1, v/v) is about quadrupled by adding a small amount of anion receptor with two urea moieties as recognition sites connecting with an ether chain. Anion receptor is an organic molecule that can associate with anions. Our anion receptor is able to associate with chloride anion. The ionic conductivity of LiCl in EC/DMC increased from 0.023 mS cm-1 (without an anion receptor) to 0.075 mS cm-1 (with a 0.05 M anion receptor). The electrolyte in the presence of a 0.05 M receptor exhibits higher ionic conductivity, rate capability, and cyclability than the electrolyte without the receptor.

Significant Improvements to Si Calendar Lifetime Using Rapid Electrolyte Screening via Potentiostatic Holds

Silicon-based lithium-ion batteries exhibit severe time-based degradation resulting in poor calendar lives. This has been identified as the major impediment towards commercialization with cycle life considered a solved issue through nanosizing and protective coatings allowing over 1000 cycles of life to be achieved. In this work, rapid screening of sixteen electrolytes for calendar life extension of Si-rich systems (70 wt% Si) is performed using the voltage hold (V-hold) protocol. V-hold significantly shortens the testing duration over the traditional open circuit voltage reference performance test allowing us to screen electrolytes within a span of two months. We find a novel ethylene carbonate (EC) free electrolyte formulation containing lithium hexafluorophosphate (LiPF6) salt, and binary solvent mix of fluoroethylene carbonate (FEC), ethyl methyl carbonate (EMC) that extends calendar life of Si cells as compared to conventional EC based electrolyte. Our coupled experimental-theoretical analysis framework provides a decoupling of the parasitic currents during V-hold, allowing us to extrapolate the capacity loss to predict semiquantitative calendar lifetimes. Subsequently, cycle aging and oxidative stability tests of the EC free system also show enhanced performance over baseline electrolyte.

Novel composite electrolyte additive for enhancing the thermal and cycling stability of SiO/C anode Li-ion battery

SiO/C anode materials have gained significant attention due to their high specific capacity and environmental friendliness in high-energy-density lithium-ion batteries (LIBs). However, due to the volume effect generated during the long-term cycle, the battery capacity will decay rapidly and cause thermal safety problems. PFPN/TTFEB is employed as a compound electrolyte additive in this study to enhance the electrochemical performance and safety of Li/SiO@C batteries. The blank control electrolyte (BE) is the commercial electrolyte, which is 1.0 M LiPF6 dissolved in ethylene carbonate (EC) and ethyl methyl carbonate (EMC) at a 3:7 vol/vol ratio. The battery with the PFPN/TTFEB addition demonstrated a substantially higher capacity retention rate than the battery with BE, increasing from 45.23 % to 74.34 %, as indicated by the electrochemical and characterization test results. This suggests that the cycling stability of the battery was improved by the synergistic influence of ethoxy(pentafluoro)cyclotriphosphazene (PFPN) and tris(2,2,2-trifluoroethyl) borate (TTFEB). In addition, a LiF-rich solid electrolyte interphase layer was observed on the surface of the anode, increasing interface stability by reducing the direct contact between the electrolyte and electrode. Differential scanning calorimetry, thermogravimetric analysis, and thermokinetic analysis revealed that the addition of PFPN/TTFEB increased apparent activation energy from 439.56 to 1090.01 kJ/mol and increased initial exothermic reaction temperature from 233.67 to 292.83 °C. The thermal stability of the battery also considerably increased, and the exothermic reaction was substantially delayed. Overall, the multifunctional electrolyte additive developed in this study offers a feasible pathway for developing LIBs with excellent cycling performance and safety.

Linear polyurethanes with excellent comprehensive properties from poly(ethylene carbonate) diol

Linear polyurethanes with excellent comprehensive properties from poly(ethylene carbonate) diol

Green Routes to Dimethyl Carbonate: A Green and Versatile Methylating Reactant

Abstract: This mini-review reports the current routes used for the production of dimethyl carbonate (DMC), a green and versatile methylating reactant widely used in organic synthesis. The use of DMC in methylation processes is also discussed. The main routes of DMC production, encompassing the reaction between phosgene and methanol and the oxidative carbonylation of methanol with CO and urea methanolysis, are summarised. However, none of them can be considered entirely green, and the drawbacks in terms of green chemistry principles are addressed. The present commercial route to DMC, which involves the initial reaction of CO2 with ethylene oxide to produce ethylene carbonate that further reacts with excess methanol, is also explored regarding the green chemistry principles. Moreover, this review focuses on the direct DMC production from the reaction of methanol and CO2, discussing catalysts and strategies to shift equilibrium. An emphasis is given to heterogeneous catalysts, especially those based on CeO2. A final remark on the production of DMC through the capture of CO2 using chitosan-derived adsorbents and renewable methanol is addressed.

CO2 derived ABA triblock all-polycarbonate thermoplastic elastomer with ultra-high elastic recovery

Although triblock polycarbonate thermoplastic elastomers (TPEs) have recently attracted great interests due to their biodegradability, insufficient attentions have been paid to improving the elastomeric properties. Through a tandem reaction strategy involving CO2 / allyl glycidyl ether (AGE) / cyclohexene oxide (CHO), poly(cyclohexene carbonate)-b-poly(allyl glycidyl ether carbonate)-b-poly(cyclohexene carbonate) (PCAC) is successfully synthesized using a metal-free Lewis acid-base pair catalyst. The synthesized PCACs are pure well-defined ABA triblock all-polycarbonate, which is supported by 1H NMR, gel permeation chromatography (GPC), and diffusion-ordered spectroscopy (DOSY). A simple modification by grafting alkylthiol chains to PCAC results in excellent TPEs named PCAC-g-S-CaH2a+1 (PCASaC). The synthesized TPEs are characterized by atomic force microscopy (AFM), thermogravimetric analysis (TG), differential scanning calorimetry (DSC), and mechanical test. They demonstrate a semi-network and semi-domain phase separation structure, wide service temperature range, good strength, high elongation, and extremely high elastic recovery properties. This low-cost, biodegradable, high-performance TPE shows great potential for applications in biomedical, wearable products, sports equipment, and other fields.

Multiple Functional Bonds Integrated Interphases for Long Cycle Sodium-Ion Batteries.

Sodium-ion batteries (SIBs) have garnered significant interest as one of the most promising energy suppliers for power grid energy storage. However, the poor electrode/electrolyte interfacial stability leads to continual electrolyte decomposition and transition metal dissolution, resulting in rapid performance degradation of SIBs. In this work, we propose a strategy integrating multiple functional bonds to regulate electrode/electrolyte interphase by triple-coupling of succinonitrile (SN), sodium hexafluorophosphate (NaPF6) and fluorinated ethylene carbonate (FEC). Theoretical calculation and experiment results show that the solvation structure of Na+ and ClO4 - is effectively reconfigured by the solvated FEC, SN and PF6 - in PC-based carbonate electrolyte. The newly developed electrolyte demonstrates increased Na+-FEC coordination, weakened interaction of Na+-PC and participation of SN and PF6 - anions in solvation, resulting in the formation of a conformal interfacial layer comprising of sodium oxynitrides (NaNxOy), sodium fluoride (NaF) and phosphorus oxide compounds (NaPxOy). Consequently, a 3 Ah pouch full cell of hard carbon//NaNi1/3Fe1/3Mn1/3O2 exhibits an excellent capacity retention of 90.4 % after 1000 cycles. Detailed postmortem analysis of interface chemistry is further illustrated by multiple characterization methods. This study provides a new avenue for developing electrolyte formulations with multiple functional bonds integrated interphases to significantly improve the long-term cycling stability of SIBs.

Inhibition of silicon-based anode interfacial volume expansion behavior by 1,3,6-hexane trinitrile additive via induced interfacial solvation effect

Silicon(Si)-based anodes exhibit higher energy density than traditional graphite anodes but suffer from significant volume changes during lithiation/delithiation, destabilizing the solid electrolyte interface (SEI) and reducing cycle stability. This study explores the effect of 1,3,6-hexane trinitrile (HTCN) on mitigating Si@C electrode expansion. The inclusion of HTCN modifies the original solvation structure of Li+, and the HTCN additive undergoes preferential coordination with Li+ because its binding energy with Li+ is larger than that of ethylene carbonate (EC). This lowers the lowest unoccupied molecular orbital (LUMO) of the HTCN-containing solvation structure, promoting preferential reduction decomposition on the anode surface. This process increases inorganic Li3N formation and produces a rich carbon-organic SEI film, effectively reducing electrolyte decomposition and Si@C anode expansion from 72.98 % to 4.46 %. Adding 1 % HTCN to Si@C/Li half-cells enhances capacity retention to 72.4 % after 100 cycles at 0.2C, significantly outperforming cells without HTCN (50.9 %). This study provides a new idea for constructing high-performance SEI films to inhibit electrode expansion by adjusting the solvation structure of Li+.

Effects of Electrolyte Solvent Composition on Solid Electrolyte Interphase Properties in Lithium Metal Batteries: Focusing on Ethylene Carbonate to Ethyl Methyl Carbonate Ratios

This study investigated the influence of variations in the mixing ratio of ethylene carbonate (EC) to ethyl methyl carbonate (EMC) on the composition and effectiveness of the solid electrolyte interphase (SEI) in lithium-metal batteries. The SEI is crucial for battery performance, as it prevents continuous electrolyte decomposition and inhibits the growth of lithium dendrites, which can cause internal short circuits leading to battery failure. Although the properties of the SEI largely depend on the electrolyte solvent, the influence of the EC:EMC ratio on SEI properties has not yet been elucidated. Through electrochemical testing, ionic conductivity measurements, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy, the formation of Li2CO3, LiF, and organolithium compounds on lithium surfaces was systematically analyzed. This study demonstrated that the EC:EMC ratio significantly affected the SEI structure, primarily owing to the promotion of the formation of a denser SEI layer. Specifically, the ratios of 1:1 and 1:3 facilitated a uniform distribution and prevalence of Li2CO3 and LiF throughout the SEI, thereby affecting cell performance. Thus, precise control of the EC:EMC ratio is essential for enhancing the mechanical robustness and electrochemical stability of the SEI, thereby providing valuable insights into the factors that either enhance or impede effective SEI formation.

Formation of solid electrolyte interphase in Li-ion batteries: Insights from temperature-accelerated ReaxFF molecular dynamics

The solid electrolyte interphase (SEI) forms between anode and electrolyte in the lithium-ion battery (LIB) and is considered to be the main contributor to LIB degradation. To understand the degradation and SEI formation, we use reactive force-field (ReaxFF) molecular dynamics to gain atomic level insights into the key phenomena. We report the effect of different reaction temperatures on SEI formation on the lithium metal anode surface in contact with pure ethylene carbonate electrolyte. The temperature elevation is found to boost the SEI formation. To investigate the structural variations of SEI, we compare the quantitative variations of key species and perform analysis using the charge distribution and radial distribution function (RDF). Our work reveals that elevated temperature of up to 700 K is appropriate for acceleration of chemical reactions during SEI formation. The study provides insights into structural variations of the lithium metal electrode and SEI at the molecular level, demonstrating that temperature-accelerated reactive molecular dynamics is an efficient and effective tool for predicting the performance and degradation of the Li-ion batteries.

Tailoring Electric Double Layer by Cation Specific Adsorption for High‐Voltage Quasi‐Solid‐State Lithium Metal Batteries

AbstractThe interfacial instability of high‐nickel layered oxides severely plagues practical application of high‐energy quasi‐solid‐state lithium metal batteries (LMBs). Herein, a uniform and highly oxidation‐resistant polymer layer within inner Helmholtz plane is engineered by in situ polymerizing 1‐vinyl‐3‐ethylimidazolium (VEIM) cations preferentially adsorbed on LiNi0.83Co0.11Mn0.06O2 (NCM83) surface, inducing the formation of anion‐derived cathode electrolyte interphase with fast interfacial kinetics. Meanwhile, the copolymerization of [VEIM][BF4] and vinyl ethylene carbonate (VEC) endows P(VEC‐IL) copolymer with the positively‐charged imidazolium moieties, providing positive electric fields to facilitate Li+ transport and desolvation process. Consequently, the Li||NCM83 cells with a cut‐off voltage up to 4.5 V exhibit excellent reversible capacity of 130 mAh g−1 after 1000 cycles at 25 °C and considerable discharge capacity of 134 mAh g−1 without capacity decay after 100 cycles at −20 °C. This work provides deep understanding on tailoring electric double layer by cation specific adsorption for high‐voltage quasi‐solid‐state LMBs.

Tailoring Electric Double Layer by Cation Specific Adsorption for High-Voltage Quasi-Solid-State Lithium Metal Batteries.

The interfacial instability of high-nickel layered oxides severely plagues practical application of high-energy quasi-solid-state lithium metal batteries (LMBs). Herein, a uniform and highly oxidation-resistant polymer layer within inner Helmholtz plane is engineered by in situ polymerizing 1-vinyl-3-ethylimidazolium (VEIM) cations preferentially adsorbed on LiNi0.83Co0.11Mn0.06O2 (NCM83) surface, inducing the formation of anion-derived cathode electrolyte interphase with fast interfacial kinetics. Meanwhile, the copolymerization of [VEIM][BF4] and vinyl ethylene carbonate (VEC) endows P(VEC-IL) copolymer with the positively-charged imidazolium moieties, providing positive electric fields to facilitate Li+ transport and desolvation process. Consequently, the Li||NCM83 cells with a cut-off voltage up to 4.5 V exhibit excellent reversible capacity of 130 mAh g-1 after 1000 cycles at 25 °C and considerable discharge capacity of 134 mAh g-1 without capacity decay after 100 cycles at -20 °C. This work provides deep understanding on tailoring electric double layer by cation specific adsorption for high-voltage quasi-solid-state LMBs.

Cathode Electrolyte Interphase Engineering for Prussian Blue Analogues in Lithium-Ion Batteries.

The increasing use of low-cost lithium iron phosphate cathodes in low-end electric vehicles has sparked interest in Prussian blue analogues (PBAs) for lithium-ion batteries. A major challenge with iron hexacyanoferrate (FeHCFe), particularly in lithium-ion systems, is its slow kinetics in organic electrolytes and valence state inactivation in aqueous ones. We have addressed these issues by developing a polymeric cathode electrolyte interphase (CEI) layer through a ring-opening reaction of ethylene carbonate triggered by OH- radicals from structural water. This facile approach considerably mitigates the sluggish electrochemical kinetics typically observed in organic electrolytes. As a result, FeHCFe has achieved a specific capacity of 125 mAh g-1 with a stable lifetime over 500 cycles, thanks to the effective activation of Fe low-spin states and the structural integrity of the CEI layers. These advancements shed light on the potential of PBAs to be viable, durable, and efficient cathode materials for commercial use.

Phosphorus-modulated surface active center reconstruction in cerium oxide for polyols conversion into carbonates

Ionic liquids (ILs) can effectively regulate the surface morphology and acid-base sites of metal oxides, which is of great significance in the preparation of metal oxide nanomaterials. Here, cerium oxide (CeO2) was prepared in phosphonium-based ILs and P-doped CeO2 materials were obtained by doping phosphorous (P) on the surface of CeO2. Moreover, the yield and selectivity for ethylene carbonate (EC) synthesis catalyzed by CeO2 catalyst prepared were 77.26 % and 95.99 % respectively. The results indicated that an appropriate content of P could generate both Lewis acidic and basic sites related to P on the catalyst surface, and P-mediated frustrated Lewis acid-base pairs (FLPs) composed of P-OH as the basic center and Ce3+ as the acidic center was constructed. This work provides a new strategy for preparing novel CeO2 catalysts and regulating acid-base sites on the surface of that.

Fully carbonate‐electrolyte‐based high‐energy‐density Li–S batteries with solid‐phase conversion

AbstractCarbonate‐electrolyte‐based lithium–sulfur (Li–S) batteries with solid‐phase conversion offer promising safety and scalability, but their reversible capacities are limited. In addition, large‐format pouch cells are paving the way for large‐scale production. This study demonstrates the in situ formation of a solid‐electrolyte interphase (SEI) as a protective layer using vinylene carbonate (VC), highlighting its industrial adaptability. A high reversible capacity is achieved by the lithiated poly‐VC SEI formed inside the cathode particles as a nanoscale ionic conduction path, along with the traditional surface protective layer. Furthermore, the severe dissolution of poly‐VC is mitigated by LiF derived from fluorine ethylene carbonate as a co‐solvent, enabling high rate performance and a long cycle life. A large 8 Ah pouch cell is successfully developed, which shows a high energy density of 400 Wh kg−1 based on the cell weight. This work demonstrates the high performance of large‐scale Li–S batteries with the in situ formation of a protective layer as a scalable technique for future applications.