Search Results (32)

The solid electrolyte interphase (SEI) on the anode of lithium-ion batteries (LIBs) has been studied thoroughly due to its crucial importance to the battery’s long-term performance. At the same time, most studies of the SEI apply ex situ characterization methods, which may introduce artifacts or misinterpretations as they do not investigate the SEI in its unaltered state immersed in liquid battery electrolyte. Thus, in this work, we focus on using the non-destructive combination of electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D) and impedance spectroscopy (EIS) in the same electrochemical cell. EQCM-D can not only probe the solidified products of the SEI but also allows for the monitoring of viscoelastic layers and viscosity changes of the electrolyte at the interphase during the SEI formation. EIS complements those results by providing electrochemical properties of the formed interphase. Our results highlight substantial differences in the physical and electrochemical properties between the SEI formed on copper and on amorphous carbon and show how formation parameters and the additive vinylene carbonate (VC) influence their growth. The EQCM-D results show consistently that much thicker SEIs are formed on carbon substrates in comparison to copper substrates. Full article

The objective of this study was to determine whether hydroxy-selenomethionine (OH-SeMet) exerts better protective effects on sows against heat stress than sodium selenite (SeNa) or seleno-yeast (SeY). A total of 60 sows (Landrace × Yorkshire) were randomly allocated into the three groups and fed a base diet supplemented with SeNa, SeY, or OH-SeMet at 0.3 mg Se/kg under a heat stress condition for a reproductive cycle. Compared to SeNa or SeY, OH-SeMet could more effectively sustain offspring growth performance, as evidenced by an increased number of live-born piglets, higher litter weight at day 21, and greater litter body weight gain from days 1 to 21. OH-SeMet was more effective in supporting endogenous redox systems, as shown by enhanced levels of TXNRD and GSH and reduced levels of GSSG in the serum of sows, improved T-AOC, TXNRD, and GSH alongside decreased MDA and GSSG in the serum of piglets, and heightened T-AOC in the jejunum of piglets. Furthermore, among the two tested organic Se sources, OH-SeMet was more effective than SeY in regulating immune responses compared to SeNa. OH-SeMet reduced inflammation-related markers CRP, HP, MAP, LPS, IL-1β, IL-6, and TNF-α, some or all of which were reduced in the serum of sows and their offspring. In addition, OH-SeMet also showed reduced glucose, TG, and NEFA levels, along with elevated insulin levels in the serum of sows. Correspondingly, among the two organic forms of Se, particularly those sows fed OH-SeMet showed better gut protection for the sows’ offspring, as indicated by a reduced crypt depth and increased villus height/crypt depth ratio in the duodenum, jejunum, and ileum than those fed SeNa. Specifically, compared to SeNa or SeY, OH-SeMet upregulated the expression of selenoproteins (GPX6, TXNRD3, GPX4, and SELENON), the tight junction protein (ZO-1), and host defense peptide gene (pBD1, pBD2, pBD3, NPG3, NPG4), along with downregulating levels of inflammation factor (IL-1β, IL-6 and TNF-α) and pro-apoptotic factor (P53) in the jejunum of piglets. Taken together, OH-SeMet more effectively mitigated the adverse effects induced by heat stress in sows and their offspring. Full article

The increasing demand for high-specific-energy lithium batteries has stimulated extensive research on the lithium metal anode owing to its high specific capacity and low electrode potential. However, the lithium metal will irreversibly react with the electrolyte during the first cycling process, forming an uneven and unstable solid electrolyte interphase (SEI) layer, which results in the non-uniform deposition of Li ions and thus the formation of lithium dendrites. This could cause a battery short circuit, resulting in safety hazards such as thermal runaway. In addition, the continuous rupture and repair of the SEIs during the repeated charge/discharge processes will constantly consume the active lithium, which leads to a significant decrease in battery capacity. An effective strategy to address these challenges is to design and construct ideal artificial SEIs on the surface of the lithium metal anode. This review analyzes and summarizes the mathematical modeling of SEI, the functional characteristics of SEIs with different components, and finally discusses the challenges faced by artificial SEIs in practical applications of lithium metal batteries and future development directions. Full article

Hard carbon (HC), which is one of the anode materials widely used in commercial sodium-ion batteries at present, suffers from a thick and unstable solid electrolyte interface (SEI) layer formed by the self-reduction in traditional carbonate-based electrolytes on its surface. This phenomenon impacts the battery’s Coulomb efficiency, cycle stability, and rate performance. In this paper, a pyrrolidinium-type di-cation ionic liquid, butyl-1,4-di(methylpyrrolidinium) di[hexafluorophosphate] (C₄di[mPy].di[PF₆]), is studied as an electrolyte additive to improve the interphase stability of the HC anode. The PF₆⁻ in C₄di[mPy].di[PF₆] enhances the coordination number between Na⁺ and PF₆⁻, and C₄di[mPy]²⁺ is preferentially reduced, jointly participating in the construction of stable, thin, dense and NaF-rich SEI films, thus laying the foundation for improving battery performance. As a result, in the carbonate electrolyte containing 2 wt% C₄di[mPy].di[PF₆], the reversible capacity of the HC/Na half-cell is increased by 14.7%, and the capacity retention rate remains at 90.4% after 400 cycles. This work provides reference for future research and design of high-performance ion liquid additives. Full article

Lithium metal batteries (LMBs) are promising candidates for electric vehicles (EVs) and next-generation energy storage systems owing to their high energy densities. The solid electrolyte interphase (SEI) on the Li metal anode plays an important role in influencing the Li deposition form and the cycle life of the LMB. However, the SEI on Li metal differs from that for other anodes, such as graphite, owing to its instability and reactivity. In addition, dendrite growth has hindered the commercial application of Li metal batteries in regular portable electronics to EVs. This review summarizes SEI formation on Li metal, dendrite formation and growth, and their impact on battery performance. In addition, we reviewed the recent progress in pretreatment strategies using materials such as polymers, carbon materials, and inorganic compounds to suppress dendritic growth. Full article

High-voltage initial anode-free lithium metal batteries (AFLMBs) promise the maximized energy densities of rechargeable lithium batteries. However, the reversibility of the high-voltage cathode and lithium metal anode is unsatisfactory in sustaining their long lifespan. In this research, a concentrated electrolyte comprising dual salts of LiTFSI and LiDFOB dissolved in mixing solvents of dimethyl carbonate (DMC) and fluoroethylene carbonate (FEC) with a LiNO₃ additive was formulated to address this challenge. FEC and LiNO₃ regulate the anion-rich solvation structure and help form a LiF, Li₃N-rich solid electrolyte interphase (SEI) with a high lithium plating/stripping Coulombic efficiency of 98.3%. LiDFOB preferentially decomposes to effectively suppress the side reaction at the high-voltage operation of the Li-rich Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ cathode. Moreover, the large irreversible capacity during the initial charge/discharge cycle of the cathode provides supplementary lithium sources for cycle life extension. Owing to these merits, the as-fabricated AFLMBs can operate stably for 80 cycles even at an ultrahigh voltage of 4.6 V. This study sheds new insights on the formulation of advanced electrolytes for highly reversible high-voltage cathodes and lithium metal anodes and could facilitate the practical application of AFLMBs. Full article

As the most promising high energy density technology, lithium metal batteries are associated with serious interfacial challenges because the electrolytes employed are unable to meet the requirements of both electrodes simultaneously, namely, the systems that work for Li metal are highly likely to be unsuitable for the cathode, and vice versa. In this study, we investigate the synergistic effects of lithium bis (oxalate) borate (LiBOB), fluoroethylene carbonate (FEC) and adiponitrile (ADN) to develop a formula that is compatible with both elements in the battery. The solid–electrolyte interphase (SEI) multi-layer generated from LiBOB and FEC successfully protects the electrolyte from the lithium and suppresses the decomposition of ADN on lithium, identified by the tiny amounts of isonitriles on the surface of the anode. Simultaneously, most of the ADN molecules remain and protect the cathode particles via the absorption layer of the nitrile groups, in the same way that this process works in commercial lithium-ion batteries. Benefiting from the stable interfacial films formed synchronously on the anode and cathode, the Li/LiNi_0.8Co_0.1Mn_0.1O₂ cells with an area capacity of ~3 mAh cm⁻² operate stably beyond 250 cycles and target the accumulated capacity to levels as high as ~653.4 mAh cm⁻². Our approach demonstrates that electrolyte engineering with known additives is a practical strategy for addressing the challenges of lithium batteries. Full article

The construction of a thin, uniform, and robust solid electrolyte interphase (SEI) film on the surface of active materials is pivotal for enhancing the overall performance of lithium-ion batteries (LiBs). However, conventional electrolytes often fail to achieve the desired SEI characteristics. In this work, we introduced 1,3,6-hexanetrinitrile (HTCN) in the baseline electrolyte (BE) of 1.0 M LiPF₆ in Ethylene Carbonate/Dimethyl Carbonate (EC/DMC) (3:7 by volume) with 5 wt.% fluoroethylene carbonate (FEC), denoted as BE-FH. By systematically investigating the influence of FEC: HTCN weight ratios on the electrochemical performance of graphite anodes, we identified an optimal composition (FEC:HTCN = 5:4 by weight, denoted as BE-FH54) that demonstrated greatly improved initial Coulombic efficiency, rate capability, and cycling stability compared with the baseline electrolyte. Deviations from the optimal FEC:HTCN ratio resulted in the formation of either small cracks or excessively thick SEI layers. The enhanced performance of BE-FH54-based LiB is mainly ascribed to the synergistic effect of FEC and HTCN in forming a robust, thin, homogeneous, and ion-conducting SEI. This research highlights the importance of rational electrolyte design in enhancing the electrochemical performance of graphite anodes in LiBs and provides insights into the role of nitrile-based additives in modulating the SEI properties. Full article

With the development of mobile electronic devices, there are more and more requirements for high-energy storage equipment. Traditional lithium-ion batteries, like lithium–iron phosphate batteries, are limited by their theoretical specific capacities and might not meet the requirements for high energy density in the future. Lithium–sulfur batteries (LSBs) might be ideal next-generation energy storage devices because they have nearly 10 times the theoretical specific capacities of lithium-ion batteries. However, the severe capacity decay of LSBs limits their application, especially at high currents. In this study, an ionic liquid (IL) electrolyte additive, TDA⁺TFSI, was reported. When 5% of the TDA⁺TFSI additive was added to a traditional ether-based organic electrolyte, the cycling performance of the LSBs was significantly improved compared with that of the LSBs with the pure traditional organic electrolyte. At a rate of 0.5 C, the discharge specific capacity in the first cycle of the LSBs with the 5% TDA⁺TFSI electrolyte additive was 1167 mAh g⁻¹; the residual specific capacities after 100 cycles and 300 cycles were 579 mAh g⁻¹ and 523 mAh g⁻¹, respectively; and the average capacity decay rate per cycle was only 0.18% in 300 cycles. Moreover, the electrolyte with the TDA⁺TFSI additive had more obvious advantages than the pure organic ether-based electrolyte at high charge and discharge currents of 1.0 C. The residual discharge specific capacities were 428 mAh g⁻¹ after 100 cycles and 399 mAh g⁻¹ after 250 cycles, which were 13% higher than those of the LSBs without the TDA⁺TFSI additive. At the same time, the Coulombic efficiencies of the LSBs using the TDA⁺TFSI electrolyte additive were more stable than those of the LSBs using the traditional organic ether-based electrolyte. The results showed that the LSBs with the TDA⁺TFSI electrolyte additive formed a denser and more uniform solid electrolyte interface (SEI) film during cycling, which improved the stability of the electrochemical reaction. Full article

Stainless steels are modern high-performance construction materials exhibiting excellent corrosion resistance, recyclability, ductility, and durability which make them appealing to use in the construction industry. However, when used as structural sections, they are subjected to localised failure in the web. This study aims to examine the structural behaviour of cold-formed low-carbon content standard austenitic 304L and 316L stainless steel channels under localised interior bearing loads. The results of 21 tests on unlipped channels with different cross-section sizes and thicknesses are presented. A nonlinear quasi-static Finite Element (FE) model is then developed. The FE model is validated against experimental test results and demonstrated good agreement in terms of bearing strength and failure modes. In addition, the experimental and FE results are used to compare the results against the results predicted in accordance with the American specification SEI/ASCE 8:2002 and European Standard EN 1993-1-4:2006. It is found that the current design equations are unreliable and too unconservative to use for cold-formed austenitic stainless steel unlipped channels, especially when compared to SEI/ASCE 8:2002, as much as 41%. Full article

In this work, dimethoxyethane (DME) and 1,3-dioxolane (DOL) are studied as the co-solvent of an advanced electrolyte for fast charging of Li-ion batteries by using lithium bis(fluorosulfonyl)imide (LiFSI) as a salt and fluorinated ethylene carbonate (FEC) as an additive. It is shown that even when used with LiFSI and FEC, neither DME nor DOL constitute a suitable electrolyte for Li-ion batteries, either because of their inability to form a robust solid-electrolyte interphase (SEI) with graphite (Gr) anodes or because of their oxidative instability against oxygen released from the delithiated LiNi_0.80Co_0.10Mn_0.10O₂ (NCM811) and LiNi_0.80Co_0.15Al_0.05O₂ (NCA), respectively. However, using 30% FEC as the co-solvent can make 1:1 DME/DOL mixture compatible with high-voltage Li-ion batteries and combining it with conventional ethylene carbonate (EC) and ethyl methyl carbonate (EMC) significantly enhances the fast charging capability of Li-ion batteries. As a result, an advanced electrolyte composed of 1.2 m (molality) LiFSI 1:1:1:2 DME/DOL/EC/EMC + 10% FEC (all by wt.) offers much improved fast-charging performances in terms of capacity and capacity retention for a 200 mAh Gr/NCA pouch cell, compared with a 1.2 m LiFSI 3:7 EC/EMC baseline electrolyte. AC impedance analysis reveals that the significant improvement is attributed to a much reduced charge transfer resistance, while the advanced electrolyte has little effect on the bulk and SEI resistances. Full article

Poly(vinylidene fluoride) (PVDF)-based composite solid electrolytes (CSEs) are attracting widespread attention due to their superior electrochemical and mechanical properties. However, the PVDF has a strong polar group -CF₂-, which easily continuously reacts with lithium metal, resulting in the instability of the solid electrolyte interface (SEI), which intensifies the formation of lithium dendrites. Herein, Tetrafluoro-1,4-benzoquinone (TFBQ) was selected as an additive in trace amounts to the PVDF/Li-based electrolytes. TFBQ uniformly formed lithophilic quinone lithium salt (Li₂TFBQ) in the SEI. Li₂TFBQ has high lithium-ion affinity and low potential barrier and can be used as the dominant agent to guide uniform lithium deposition. The results showed that PVDF/Li-TFBQ 0.05 with a mass ratio of PVDF to TFBQ of 1:0.05 had the highest ionic conductivity of 2.39 × 10⁻⁴ S cm⁻¹, and the electrochemical stability window reached 5.0 V. Moreover, PVDF/Li-TFBQ CSE demonstrated superior lithium dendrite suppression, which was confirmed by long-term lithium stripping/sedimentation tests over 2000 and 650 h at a current of 0.1 and 0.2 mA cm⁻², respectively. The assembled solid-state LiNi_0.6Co_0.2Mn_0.2O₂||Li cell showed an excellent performance rate and cycle stability at 30 °C. This study greatly promotes the practical research of solid-state electrolytes. Full article

Aqueous zinc batteries (AZBs) are one of the most promising large-scale energy storage devices by virtue of their high specific capacity, high degree of safety, non-toxicity, and significant economic benefits. However, Zn anodes in aqueous electrolyte suffer from zinc dendrites and side reactions, which lead to a low coulombic efficiency and short life cycle of the cell. Since electrolytes play a key role in the Zn plating/stripping process, versatile strategies have been developed for designing an electrolyte to handle these issues. Among these strategies, electrolyte additives are considered to be promising for practical application because of the advantages of low cost and simplicity. Moreover, the resulting electrolyte can maximally preserve the merits of the aqueous electrolyte. The availability and effectiveness of additives have been demonstrated by tens of research works. Up to now, it has been essential and timely to systematically overview the progress of electrolyte additives in mild acidic/neutral electrolytes. These additives are classified as metal ion additives, surfactant additives, SEI film-forming additives, and complexing additives, according to their functions and mechanisms. For each category of additives, their functional mechanisms, as well as the latest developments, are comprehensively elaborated. Finally, some perspectives into the future development of additives for advanced AZBs are presented. Full article

Due to their low cost, suitable working potential and high stability, carbon materials have become an irreplaceable anode material for alkali ion batteries, such as lithium ion batteries, sodium ion batteries and potassium ion batteries. During the initial charge, electrolyte is reduced to form a solid electrolyte interphase (SEI) on the carbon anode surface, which is an electron insulator but a good ion conductor. Thus, a stable surface passivation is obtained, preventing the decomposition of electrolyte in the following cycles. It has been widely accepted that SEI is essential for the long-term performance of batteries, such as calendar life and cycle life. Additionally, the initial coulombic efficiency, rate capability as well as safety of the batteries are dramatically influenced by the SEI. Extensive research efforts have been made to develop advanced SEI on carbon materials via optimization of electrolytes, including solutes, solvents and additives, etc. However, SEI is produced via the catalytic decomposition of electrolyte by the surface of electrode materials. The surface structure of the carbon material is another important aspect that determines the structure and property of SEI, which little attention has been paid to in previous years. Hence, this review is dedicated to summarizing the impact of the surface structure of carbon materials on the composition, structure and electrochemical performance of the SEI in terms of surface atoms exposed, surface functionalization, specific surface area and pore structure. Some insights into the future development of SEI from the perspective of carbon surface are also offered. Full article

Silicon-based anode materials are considered one of the highly promising anode materials due to their high theoretical energy density; however, problems such as volume effects and solid electrolyte interface film (SEI) instability limit the practical applications. Herein, silicon nanoparticles (SiNPs) are used as the nucleus and anatase titanium dioxide (TiO₂) is used as the buffer layer to form a core-shell structure to adapt to the volume change of the silicon-based material and improve the overall interfacial stability of the electrode. In addition, silver nanowires (AgNWs) doping makes it possible to form a conductive network structure to improve the conductivity of the material. We used the core-shell structure SiNPs@TiO₂/AgNWs composite as an anode material for high-efficiency Li-ion batteries. Compared with the pure SiNPs electrode, the SiNPs@TiO₂/AgNWs electrode exhibits excellent electrochemical performance with a first discharge specific capacity of 3524.2 mAh·g⁻¹ at a current density of 400 mA·g⁻¹, which provides a new idea for the preparation of silicon-based anode materials for high-performance lithium-ion batteries. Full article