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Advanced All-Fluorinated Electrolytes for Extended Cycle Life and Stability of Li||SPAN Batteries
Achieving long-term stability and consistent capacity in lithium (Li) metal batteries with sulfurized polyacrylonitrile (SPAN) cathodes requires precisely engineered electrolytes to optimize interphase formation and redox reversibility. Here, this study presents 1,1-difluoro-2-(2-methoxyethoxy)ethane (DFE)-based localized high-concentration electrolytes (LHCEs), incorporating fluorinated components such as salt, solvating solvent, and diluent for improved electrode stability. Molecular dynamics simulations and surface analyses reveal that the DFE-LHCE with 1,2-bis(1,1,2,2-tetrafluoroethoxy)ethane (BTFEE) diluent produces uniform and robust interphase layers on both cathode and anode, enriched with inorganic species like LiF and Li 2 O. These properties lead to prolonged redox reversibility of the SPAN cathode, suppressed side reactions, and extended cycle life for Li||SPAN cells. Remarkably, DFE-BTFEE-LHCE enables Li||SPAN coin cells with an areal capacity of ∼7 mAh cm -2 for SPAN to retain 81.3% capacity after 200 cycles and pouch cells of 0.12 Ah with 8 mAh cm -2 of SPAN and lean electrolyte to maintain 96.4% capacity over 80 cycles. These findings pave the way for advancing Li||SPAN battery technologies.
Performance of a hybrid chemical/mechanical heat pump
The authors present the design and preliminary results of the performance of a hybrid chemical/mechanical, low-lift (20 C) heat pump. Studies have indicated that this heat pump has several advantages over the traditional single fluid vapor compression (reverse Rankine) heat pump. Included in these benefits are: 1) increased COPc due to the approximation of the cycle to the Lorenz cycle and due to the availability of the heat of solution, along with the heat of vaporization, to provide cooling; and 2) ease of variation in system cooling capacity by changing the fluid composition. The system performance is predicted for a variety of refrigerant-absorbent pairs. Cooling capacity is determined for systems operating with ammonia as the refrigerant and lithium nitrate and sodium thiocyanate as the absorbents and also with water as the refrigerant and magnesium chloride, potassium hydroxide, lithium bromide, sodium hydroxide, and sulfuric acid as the absorbents. Early indications have shown that the systems operating with water as the refrigerant operate at 2-4 times the capacity of the ammonia-refrigerant-based systems. Using existing working fluids in the proposed innovative design, a coefficient-of-performance improvement of 21 percent is possible when compared to the best vapor compression systems analyzed.
Yolk-shell nanoparticle, method and applications
A nanoparticle and a method for fabricating the nanoparticle utilize a decomposable material yoke located within permeable organic polymer material shell and separated from the permeable organic polymer material shell by a void space. When the decomposable material yoke comprises a sulfur material and the permeable organic polymer material shell comprises a material permeable to both a sulfur material vapor and a lithium ion within a battery electrolyte the nanoparticle may be used within an electrode for a Li/S battery absent the negative effects of battery electrode materials expansion.
Yolk-shell nanoparticle, method and applications
A nanoparticle and a method for fabricating the nanoparticle utilize a decomposable material yoke located within permeable organic polymer material shell and separated from the permeable organic polymer material shell by a void space. When the decomposable material yoke comprises a sulfur material and the permeable organic polymer material shell comprises a material permeable to both a sulfur material vapor and a lithium ion within a battery electrolyte the nanoparticle may be used within an electrode for a Li/S battery absent the negative effects of battery electrode materials expansion.
Yolk-shell nanoparticle, method and applications
A nanoparticle and a method for fabricating the nanoparticle utilize a decomposable material yoke located within permeable organic polymer material shell and separated from the permeable organic polymer material shell by a void space. When the decomposable material yoke comprises a sulfur material and the permeable organic polymer material shell comprises a material permeable to both a sulfur material vapor and a lithium ion within a battery electrolyte the nanoparticle may be used within an electrode for a Li/S battery absent the negative effects of battery electrode materials expansion.
Solid Electrolytes for Li–S Batteries: Solid Solutions of Poly(ethylene oxide) with Li x PON- and Li x SiPON-Based Polymers
We report here efforts to synthesize free-standing, dry polymer electrolytes that exhibit superior ionic conductivities at ambient for Li–S batteries. Co-dissolution of poly(ethylene oxide) (PEO) (M n 900k) with Li x PON and Li x SiPON polymer systems at a ratio of approximately 3:2 followed by casting provides transparent, solid-solution films 25–50 μm thick, lowering PEO crystallinity, and providing measured impedance values of 0.1–2.8 × 10 –3 S/cm at ambient. These values are much higher than simple PEO/Li + salt systems. These solid-solution polymer electrolytes (PEs) are (1) thermally stable to 100 °C; (2) offer activation energies of 0.2–0.5 eV; (3) suppress dendrite formation; and (4) enable the use of lithium anodes at current densities as high as 3.5 mAh/cm 2 . Here, galvanostatic cycling of SPAN/PEs/Li cell (SPAN = sulfurized, carbonized polyacrylonitrile) shows discharge capacities of 1000 mAh/g sulfur at 0.25C and 800 mAh/g sulfur at 1C with high coulumbic efficiency over 100 cycles.
Methods of making lithium ion conducting sulfide glass
A lithium ion-conductive solid electrolyte including a freestanding inorganic vitreous sheet of sulfide-based lithium ion conducting glass is capable of high performance in a lithium metal battery. Such an electrolyte is also manufacturable, and readily adaptable for battery cell and cell component manufacture, in a cost-effective, scalable manner using an automated machine based system, apparatus and methods based on inline spectrophotometry to assess and inspect the quality of such vitreous solid electrolyte sheets and associated components. Suitable manufacturing methods can involve providing a sulfur precursor, providing a boron precursor material having lithium as a second constituent, combining the sulfur and boron precursor materials to form a precursor mixture, melting the mixture, and cooling the melt to form a solid lithium ion conducting glass. The glass may have a Li+ conductivity of at least 10 −5 S/cm. The boron precursor material may be synthesized by reducing boron oxide to boron metal by heating the boron oxide in direct contact with lithium metal.
Multifunctional, Self-Healing Polyelectrolyte Gels for Long-Cycle-Life, High-Capacity Sulfur Cathodes in Li-S Batteries (FY2020 Final Report)
The project aims to develop polyelectrolyte gels consisting of partially crosslinked ionomer, interpenetrated with self-healing/polysulfide-trapping chains and swelled with a mixture of room temperature ionic liquid (RTIL) and lithium salt. To our knowledge, no other sulfur-based cathode design has combined self-healing behavior, polysulfide containment, and lithium dendrite suppression into a single design. We have demonstrated the benefits of multifunctional ionomer gel polyelectrolytes / gel cathodes with self-healing properties, as well as chemical modification of mesoporous carbons for S/C composite cathodes. Success of the proposed program of study would have wide ranging impact on the electric vehicle industry and society as a whole. A Li-S battery system with the capability of doubling lithium-ion energy density would enable the production of lighter, longer range electric vehicles at a cost that is affordable to the average U.S. household. The availability of such vehicles should lead to wide-ranging adoption over the coming years which, in combination with increased renewable electricity generation, will drastically decrease carbon emissions across the country and reduce U.S. dependency on fossil fuel sources.
A solid electrolyte interphase to protect the sulfurized polyacrylonitrile (SPAN) composite for Li–S batteries: computational approach addressing the electrolyte/SPAN interfacial reactivity
This study addresses the reactivity of multiple solvents and lithium bis(fluorosulfonyl)imide (LiFSI) at the interface with sulfurized polyacrylonitrile (SPAN) in multiple stages of lithiation via ab initio molecular dynamics simulations. Here, both ether 1,3-dioxolane (DOL) and dimethyl carbonate (DMC) proved stable on the lithiated SPAN surface regardless of the lithium content, meaning that neither of these species likely contributes to growing a solid electrolyte interphase (SEI) coating to protect the SPAN composite. Conversely, cyclic carbonates, ethylene carbonate (EC) and fluoroethylene carbonate (FEC) are shown to be very active. The EC reduction occurs only on a highly lithiated surface with a 3.0 Li/S molar ratio, the equivalent of the SPAN composite in an over-discharge regime with voltages close to 0.0 V vs. Li/Li + . The FEC reduction starts with a 2.0 Li/S molar ratio and above, suggesting that FEC could act as a useful additive in electrolyte formulations with EC. Both EC and FEC follow multiple reduction mechanisms to produce complex reduction products and LiF in the FEC case. We provide a mechanistic description for each detected decomposition path. The LiFSI salt also proves reactive against the lithiated SPAN surface. The FSI – defluorination is the dominant reduction path. However, the SO 2 NSO 2 F – and SO 2 NSO 2 2– species proved stable against S–N cleavage. This behavior makes the LiFSI salt a potential candidate for SPAN-based Li–S batteries because it produces LiF without releasing SO 2 .
Extraction of lithium from battery recycling wastewater using synergistic D2EHPA and TBP
The recycling of spent lithium-ion batteries (LIBs) poses significant challenges, including the generation of large volumes of chemically complex wastewater. The composition of this wastewater is influenced by both the intrinsic chemistry of the batteries and the specific recycling processes employed. Notably, this wastewater contains economically valuable components, such as lithium, which can be recovered. Here, in this study, a solvent extraction (SX) process was investigated as a method to recover lithium from battery recycling wastewater, especially from anode-washing stage. Initially, various commercial extractants were evaluated, including di(2-ethylhexyl)phosphoric acid (D2EHPA), mono-2-ethylhexyl (2-ethylhexyl)phosphonate (PC88A), bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272), 2-hydroxy-5-nonylacetophenone oxime (LIX 84-I), tri-butyl phosphate (TBP), and their combinations. Among these, D2EHPA + TBP demonstrated a synergism to advance and maximize the lithium extraction. Subsequently, the effects of key parameters, including D2EHPA concentration, TBP concentration, contact time, initial pH, and aqueous-to-organic (A/O) phase ratio, were systematically investigated and optimized. A two-stage SX approach was employed to enhance lithium recovery. Under the optimized conditions of 30.0 vol% D2EHPA, 10.0 vol% TBP, 10 min of contact time, and a 1:1 A/O phase ratio, a lithium extraction efficiency of more than 88% in a two-stage solvent extraction was achieved. Lithium was subsequently stripped from the loaded organic solution using sulfuric acid (H 2 SO 4 ). Using 2.0 M H 2 SO 4 , lithium stripping was achieved after two counter-current stripping stages at an organic-to-aqueous (O/A) phase ratio of 6:1. This stripping process enriched the lithium concentration by a factor of four compared to the original lithium concentration in the anode-washing wastewater. The recyclability of the synergistic D2EHPA + TBP system was also evaluated over four extraction-stripping cycles. The results demonstrated that the system maintained high extraction and stripping efficiencies.
Lithium superoxide-based high rate Li-Air batteries enabled by Di-iridium sulfur bridge active sites
Li-oxygen (Li-O 2 ) batteries can potentially provide much higher energy density than Li-ion batteries; however, the practical application of these batteries is hindered due to several drawbacks such as low current rates and high overpotential for the charging process. Here, in this paper, we report a novel Li-Air battery system that operates under high current rates (up to 1mAcm -2 ) with LiO 2 as the primary discharge product instead of the commonly reported Li 2 O 2 . This LiO 2 based battery at high rates is through a combination of an as-synthesized new one-dimensional (1D) transition metal trichalcogenide mid-entropy alloy of SnIrS 3.6 as a cathode catalyst and an electrolyte blend with a SnI 2 bi-functional additive. It is revealed that SnIrS 3.6 has a microporous structure composed of six- and five-coordinated metal atoms, forming octahedral and triangular bipyramids which has not been observed in other layered chalcogeide materials. DFT calculations reveal that the SnIrS 3.6 structure can result in LiO 2 formation through di-iridium sulfur bridge active sites that results in strong binding of O 2 and LiO 2 preventing disproportionation to Li 2 O 2 and enabling high rates. This finding will open a new perspective in designing advanced LiO 2 -based Li-O 2 batteries for real practices.
Improved ceramic heat exchange material
Improved corrosion resistant ceramic materials that are suitable for use as regenerative heat exchangers for vehicular gas turbines is reported. Two glass-ceramic materials, C-144 and C-145, have superior durability towards sulfuric acid and sodium sulfate compared to lithium aluminosilicate (LAS) Corning heat exchange material 9455. Material C-144 is a leached LAS material whose major crystalline phase is silica keatite plus mullite, and C-145 is a LAS keatite solid solution (S.S.) material. In comparison to material 9455, material C-144 is two orders of magnitude better in dimensional stability to sulfuric acid at 300 C, and one order of magnitude better in stability to sodium sulfate at 1000 C. Material C-145 is initially two times better in stability to sulfuric acid, and about one order of magnitude better in stability to sodium sulfate. Both C-144 and C-145 have less than 300 ppm delta L/L thermal expansion from ambient to 1000 C, and good dimensional stability of less than approximately 100 ppm delta L/L after exposure to 1000 C for 100 hours. The glass-ceramic fabrication process produced a hexagonal honeycomb matrix having an 85% open frontal area, 50 micrometer wall thickness, and less than 5% porosity.
Composite Lithium Metal Structure to Mitigate Pulverization and Enable Long‐Life Batteries
In lithium metal batteries, non‐uniform stripping of lithium results in pit formation, which promotes subsequent non‐uniform, dendritic deposition. This viscous cycle leads to pulverization of lithium which promotes cell shorting or capacity degradation, symptoms further exaggerated by high electrode areal loading and lean electrolytes. Here, to address this challenge, a composite lithium metal anode is engineered that contains uniformly distributed, nanometer‐sized carbon particles. This composite lithium is shown to strip more uniformly since the growth of non‐uniform pits is intercepted by the carbon particles. This mechanism is corroborated by a continuum electrochemical model. Subsequent lithium deposition on carbon particles is also found to be more uniform than on the surface with irregular pits. Notably, the pulverization rate of composite lithium is 26 times slower than that of commercial lithium. Moreover, in a Li‐S battery with sulfurized polyacrylonitrile cathode, the use of the composite anode extends the cycle life by three times when the areal capacity is 8 mAh cm −2 . The approach of using an engineered lithium composite structure to address challenges during both stripping and plating can inform future designs of lithium metal anodes for high areal capacity operations.
Power Sources Symposium, 27th, Atlantic City, N.J., June 21-24, 1976, Proceedings
A lithium-chlorine rechargeable battery is considered along with an FeS electrode development for a secondary Li5Si-FeS battery, the sodium-sulfur battery, nickel battery systems for electric vehicles, reactions in lithium thionyl chloride cells, progress in the development of lithium inorganic batteries, a stable electrolyte for Li/SO2 reserve cells, and rechargeable lithium transition metal sulfide batteries. Attention is also given to thermal runaway tests on nickel-cadmium aircraft batteries, the development of nickel-zinc batteries for aircraft, an evaluation of sealed lead acid batteries for aircraft applications, the charging of sealed lead-acid batteries, hydrogen recombination in sealed nickel-cadmium cells, the characteristics of nickel-hydrogen flight cells, the lithium-iodine cell, low power methanol fuel cells, and a nuclear battery hybrid configuration study.
Heteroatom-Doped Flash Graphene
Heteroatom doping can effectively tailor the local structures and electronic states of intrinsic two-dimensional materials, and endow them with modified optical, electrical, and mechanical properties. Recent studies have shown the feasibility of preparing doped graphene from graphene oxide and its derivatives via some post-treatments, including solid-state and solvothermal methods, but they require reactive and harsh reagents. However, direct synthesis of various heteroatom-doped graphene in larger quantities and high purity through bottom-up methods remains challenging. Here, we report catalyst-free and solvent-free direct synthesis of graphene doped with various heteroatoms in bulk via flash Joule heating (FJH). Seven types of heteroatom-doped flash graphene (FG) are synthesized through millisecond flashing, including single-element-doped FG (boron, nitrogen, oxygen, phosphorus, sulfur), two-element-co-doped FG (boron and nitrogen), as well as three-element-co-doped FG (boron, nitrogen, and sulfur). Here, a variety of low-cost dopants, such as elements, oxides, and organic compounds are used. The graphene quality of heteroatom-doped FG is high, and similar to intrinsic FG, the material exhibits turbostraticity, increased interlayer spacing, and superior dispersibility. Electrochemical oxygen reduction reaction of different heteroatom-doped FG is tested, and sulfur-doped FG shows the best performance. Lithium metal battery tests demonstrate that nitrogen-doped FG exhibits a smaller nucleation overpotential compared to Cu or undoped FG. The electrical energy cost for the synthesis of heteroatom-doped FG synthesis is only 1.2 to 10.7 kJ g –1 , which could render the FJH method suitable for low-cost mass production of heteroatom-doped graphene.
Electrode-omics reveals epochs in silicon anode evolution underpinning electrochemomechanical resilience
Here, we advance electrode-omics to identify evolutionary bursts by which ethereal locally superconcentrated electrolytes (LSCEs) mitigate silicon anode degradation through its epochs of electrochemical and chemical reactions. Anode composites form initially at high potential from ethereal solvent and anion [bis(fluorosulfonyl)imide (FSI − )] redox. A first evolutionary burst at lower potential enriches composites with lithium alkoxides (LiO–R) and lithium oxide (Li 2 O) and depletes sulfur oxides (SO x ) species. As the cells are cycled, a second evolutionary burst takes place, where previously extinct SO x species reemerge concurrently with a loss of LiO–R and Li 2 O. This identifies reactions rooted in “SuFEx” chemistry, where oxoanionic LiO–R and Li 2 O species, electrochemically generated in the solid-electrolyte interphase, chemically react with FSI − in the electrolyte to form emergent species. This sequence of evolutionary bursts produces a mechanically resilient composite that reduces silicon anode cracking over hundreds of cycles, leading to overpotential increase of only ~0.01 volts after 200 cycles.
Vitreous solid electrolyte sheets of Li ion conducting sulfur-based glass and associated structures, cells and methods
A lithium ion-conductive solid electrolyte including a freestanding inorganic vitreous sheet of sulfide-based lithium ion conducting glass is capable of high performance in a lithium metal battery by providing a high degree of lithium ion conductivity while being highly resistant to the initiation and/or propagation of lithium dendrites. Such an electrolyte is also itself manufacturable, and readily adaptable for battery cell and cell component manufacture, in a cost-effective, scalable manner.