Improved Lithium-Sulfur Batteries for Electric Vehicles

Lithium-sulfur battery with high specific capacity by optimizing the ratio of sulfur in the electrode to sulfur dissolved in the electrolyte. This involves controlling the amount of elemental sulfur in the electrode compared to the amount that elutes into the electrolyte during charging/discharging. A target ratio of less than 15% of sulfur in the electrolyte relative to the electrode sulfur helps prevent capacity loss due to sulfur elution.

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Cathode materials for lithium-sulfur batteries that improve performance and overcome limitations of using sulfur as the active cathode material. The cathode comprises a mixture of electroactive sulfur, like S8 or Li2S, and non-sulfur electroactive materials, like metal chalcogenides or oxides. The blended cathode has discharge voltage profiles that approximate sulfur's, allowing full sulfur conversion. The non-sulfur materials prevent sulfur agglomeration and enable high sulfur loading. This improves cycling and reduces capacity fade compared to pure sulfur cathodes.

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High-energy lithium-sulfur soft pack battery with improved cycling stability and capacity. The battery has a composite positive electrode with a buffer layer made of a mixture of carbon and a rare earth compound. This buffer layer is integrated with the positive electrode and current collector. The buffer layer reduces internal resistance, inhibits expansion and polysulfide shuttling in the positive electrode during charging/discharging. The negative electrode has a thin lithium layer coated with a conductive polymer to prevent dendrite growth. The high loading sulfur anode is 10mg/cm2. The battery has energy density of 500Wh/kg.

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Lithium-sulfur battery with long cycle life and 100% coulombic efficiency by using a solid-phase conversion reaction mechanism instead of the dissolution-deposition reaction mechanism found in conventional lithium-sulfur batteries. The battery uses a sulfur-carbon composite anode, lithium cathode, and an electrolyte with a specific mixture of organic solvent and vinylene carbonate (VC). The VC forms a stable and dense interfacial film to isolate the active materials from the electrolyte and prevent polysulfide dissolution, enabling a solid-phase conversion reaction and avoiding the dissolution loss of active materials. This allows 100% coulombic efficiency and improved cycle stability compared to conventional lithium-sulfur batteries with carbonate electrolytes.

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Lithium-sulfur battery without a lithium metal anode for improved safety and cycle life compared to conventional lithium-sulfur batteries. The battery structure omits the lithium metal anode and instead uses a sulfur anode containing a lithium source, a sulfur-based positive electrode, an electrolyte, and an anode containing a lithium source. This allows replacing the lithium metal anode with a sulfur anode and lithium source in the cathode and anode to avoid dendrite growth and side reactions. The sulfur anode is made by mixing sulfur, carbon, binder, and lithium source on a current collector. The anode containing lithium source is made similarly with sulfur, carbon, binder, and lithium source.

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Lithium-sulfur battery with improved performance by reducing sulfur dissolution and shuttle effects. The battery uses a specially designed positive electrode pole piece that has a current collector, a positive electrode layer, and a separator layer. The positive electrode layer is made of spherical sulfur particles with a conductive agent and binder. The separator layer contains materials like acetylene black, activated carbon, carbon nanotubes, and long carbon fibers. This configuration reduces sulfur dissolution and improves cycling by trapping any dissolved sulfur in the separator.

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Lithium-sulfur battery with improved cycling performance and reduced sulfur shuttle effect. The battery has a lithium-sulfur chemistry with a lithium-sulfur positive electrode and an electrolyte containing a specific compound. The compound, which has formulas containing S-S, S-Se, or Se-Se bonds, is added to the electrolyte at a mass percentage E. The positive electrode porosity P is also measured. The battery has improved cycle life and capacity retention when the ratio E/P is 0.02 to 0.3, preferably 0.05 to 0.17. This is attributed to the compound preventing sulfur shuttle and the porosity allowing ion conduction.

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Electrolyte solution for lithium-sulfur secondary batteries that improves battery life and capacity retention. The electrolyte contains vinylene carbonate at specific concentrations when used in lithium-sulfur batteries with sulfur-based cathodes. The vinylene carbonate helps prevent polysulfide dissolution during cycling that degrades battery performance. The electrolyte composition is 10-100 wt% vinylene carbonate in the solvent.

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Solid-state lithium-sulfur battery with improved safety and cycling performance compared to liquid electrolyte batteries. The battery has a solid electrolyte sandwiched between a cathode containing sulfur, carbon, and a solid electrolyte, and an anode of lithium metal. The cathode also has a small amount of copper. The copper content is limited to 0.37 g/Ah discharge capacity and the charged state Cu/Li ratio is less than 0.81 to prevent excessive copper plating. This composition and intercalated solid electrolyte between the cathode and anode avoids issues like thermal runaway, electrolyte leakage, and shuttle effects that can occur with liquid electrolytes.

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Lithium-sulfur secondary battery with improved energy density and cycle life by using separate electrolytes for the positive and negative electrodes. The battery has a heterogeneous electrolyte system where a first electrolyte containing a low boiling point solvent and lithium salt is used between the positive electrode and separator, and a second electrolyte with lithium salt is used between the negative electrode and separator. This prevents sulfur loss and corrosion of the lithium metal negative electrode during cycling.

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Lithium-sulfur solid-state battery with improved performance by forming a lithium oxide film on the negative electrode surface. The film is created through contact with an electrolyte containing nitrate or nitrite ions, or by applying nitric acid or nitrite to the negative electrode. This film reduces interfacial resistance and improves cycle characteristics compared to a bare negative electrode. It also prevents dendrite growth on the negative electrode during cycling.

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Lithium-sulfur battery with improved capacity and cycle life. The battery uses sulfur as the positive electrode active material, lithium metal as the negative electrode active material, and an electrolyte with a weight ratio of 2.9-3.2 parts electrolyte to 1 part sulfur. This composition reduces overvoltage and provides better overall performance compared to conventional lithium-sulfur batteries. The lower electrolyte weight ratio mitigates issues like capacity fade, shuttle effects, and polysulfide dissolution.

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Electrochemical cell with low porosity cathode and low polysulfide solvent electrolyte to enable high sulfur utilization and cycle life in lithium-sulfur batteries. The cathode has a porosity less than 40% to prevent polysulfide shuttle. The low porosity is achieved by grinding sulfur and carbon powder to reduce particle size. This increases interfacial contact between sulfur and carbon to enable high utilization via a solid-state mechanism. The electrolyte has a low polysulfide solubility to suppress shuttle. Applying pressure during cell cycling further improves sulfur utilization and cycle life. The lower porosity cathode and electrolyte prevent polysulfide shuttle without requiring additives.

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Electrolyte composition for lithium-sulfur batteries that improves performance and storage characteristics. The electrolyte contains N-containing additives dissolved in non-aqueous solvents. The N-containing additives help form a more protective SEI layer on the lithium anode, reducing lithium consumption reactions. This improves sulfur utilization, charge-discharge efficiency, and self-discharge rates compared to conventional electrolytes.

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Lithium-sulfur battery with reduced liquid-sulfur ratio and low lithium salt concentration in the electrolyte to improve energy density. By reducing the liquid-sulfur ratio below 3.5 and lowering the lithium salt concentration in the electrolyte to 0.05-0.4 mol/L, the battery's energy density can be increased. The lower liquid-sulfur ratio reduces the overall battery mass. The lower lithium salt concentration improves polysulfide solubility, promoting discharge capacity, and reduces electrolyte density further boosting energy density.

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Easy and high capacity manufacturing method for lithium-sulfur batteries with sulfur-based positive electrodes. The method involves simple steps like mixing sulfur, carbon, lithium salt, solvent, and polymer to form a slurry, coating it on a substrate, evaporating the solvent to create a self-standing sulfur sheet, and stacking it with spacers and a negative electrode to make the battery. This avoids complex processes like nucleating sulfur on carbon nanotubes. The resulting lithium-sulfur battery has high capacity and energy density due to the sulfur-rich positive electrode.

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Lithium sulfur battery with uniform electrode structure to reduce cracking during high loading. The battery has a sandwich-type positive electrode with sulfur-based material on both the current collector and separator. This avoids cracks in the electrode after drying during manufacturing compared to just coating the separator. The sulfur layers on both components create a uniform structure with reduced cracking when the battery is charged/discharged at high loading.

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High energy density lithium-sulfur secondary battery that overcomes the limitations of existing lithium-sulfur batteries. The battery uses a positive electrode with a high surface area carbon material to improve sulfur reactivity. This allows using a low electrolyte volume to prevent sulfur elution without sacrificing capacity. The low electrolyte volume prevents sulfur dissolution and adherence to the anode, enabling better capacity retention compared to conventional lithium-sulfur batteries.

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Rechargeable lithium-sulfur battery with high energy density and improved cycling stability by addressing issues like dendrite formation, capacity fade, and cycle life. The battery uses a specific electrolyte composition and cell design. The electrolyte has a higher concentration of lithium salt in the cathode side versus anode side. This prevents lithium polysulfide shuttle and anode dendrites. The cathode has a sulfur-containing active material mixed with exfoliated graphite worms. The anode has lithium metal. A protective layer between them prevents dendrites. This design allows high sulfur utilization and capacity with stable cycling.

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Lithium-sulfur secondary battery with high energy density by optimizing the positive electrode, separator, and electrolyte to suppress lithium polysulfide elution. The positive electrode uses a microporous carbon-sulfur composite with an SC factor of 0.45 or higher. This composite has a high sulfur utilization and reduces polysulfide dissolution during cycling. The microporous carbon provides mechanical stability and prevents polysulfide elution.

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