Lithium-sulfur battery

Abstract

The invention discloses a lithium-sulfur battery adopting a multi-layer composite separator. The multi-layer composite separator is characterized in that one side surface of a substrate separator is coated with a polymer layer A, the other side surface of the substrate separator is coated with an inorganic solid material layer and a polymer layer B, and the inorganic solid material layer is located between the substrate separator and the polymer layer B. The mechanical strength of the separator can be improved by the inorganic solid material layer, when a ceramic material with a lithium ion conduction function is used, the ionic conductivity of the separator can be improved effectively, and a polarization effect in charge-discharge processes is reduced. An electrolyte of the lithium-sulfurbattery contains an additive, therefore, interface state of a cathode, an anode and the separator is improved, charge-discharge current on the lithium anode surface is more uniform, activity of the lithium anode in the lithium anode can be reduced effectively, possibility of formation of lithium dendrites is reduced greatly, and use stability of the lithium anode is improved.

Description

technical field

[0001] The invention belongs to the field of lithium-sulfur batteries, in particular to a multilayer composite separator for lithium-sulfur batteries. Background technique

[0002] In today's society, while the rapid economic development enables people to obtain ample material life, the energy crisis and environmental pollution problems are increasingly perplexing the survival of human beings. In this severe situation, the development of new green energy and renewable energy, as well as the corresponding energy conversion and storage technologies are urgent problems to be solved by current scientific and technological workers. Due to the current problems, new energy vehicles and other electronic devices emerged as the times require. However, the lithium-ion batteries currently in circulation in the market have low energy density and cannot meet the high energy density requirements of new electrical equipment. It is imperative to develop a new power supply sy...

Examples

Embodiment 1

[0033] Weigh 5g of PVDF and 95g of NMP to prepare a PVDF solution with a mass fraction of 5%, then mix titanium oxide ceramic particles with a particle size of 50nm with the PVDF solution to make a slurry, and the mass fraction of the ceramic particles in the slurry is 65%. Coat the uniformly mixed inorganic ceramic slurry on one side of a commercially available polyethylene diaphragm, then dry the diaphragm at 60°C in a blast oven for 8 hours, and then dry it in a vacuum oven at 60°C after the solvent evaporates. After 12 hours, the thickness of the inorganic ceramic layer was measured to be 5 μm.

[0034] The PVDF of 8g is taken by weighing, is dissolved in NMP, and preparation PVDF content is 8% solution, and the slurry that obtains is coated on the both sides of above-mentioned single-layer composite diaphragm by pulling method, then diaphragm is heated in blast oven at 60 ℃ drying for 8 hours, after the solvent evaporates, then drying in a vacuum oven at 60 ℃ for 12 hours...

Embodiment 2

[0036] Sulfur-carbon composite (sulfur loading is 70%), acetylene black, and PVDF are prepared by coating the slurry with 7:2:1 on the carbon-coated aluminum foil to prepare the positive electrode, and the metal lithium foil is used as the negative electrode, obtained in Example 1. The diaphragm, the electrolyte uses 0.85M LiN (CF 3 SO 2 ) 2 ,DOL:DME=1:2(V:V),0.3M LiNO 3 , Assemble the CR2016 button battery, and test the cycle performance of the battery. When the battery test temperature is 25°C and the test rate is 0.05C, the first discharge specific capacity of the battery is 1239mAh / g, and the capacity retention rate still reaches 87% after 80 cycles. When the battery test temperature is 25°C and the test rate is 0.08C, the first discharge specific capacity of the battery is 1165mAh / g, and the capacity retention rate still reaches 81% after 80 cycles.

Embodiment 3

[0038] Weigh 5g of PVDF and 95g of NMP to prepare a PVDF solution with a mass fraction of 5%, and then mix ultrafine boron nitride ceramic particles with the PVDF solution to make a slurry, and the mass fraction of the ceramic particles in the slurry is 65%. Coat the uniformly mixed inorganic ceramic slurry on one side of a commercially available polyethylene diaphragm, then dry the diaphragm at 60°C in a blast oven for 8 hours, and then dry it in a vacuum oven at 60°C after the solvent evaporates. After 12 hours, the thickness of the inorganic ceramic layer was measured to be 5 μm.

[0039] The PVDF of taking 10g is dissolved in NMP, and preparation PVDF content is 10% solution, the slurry that obtains is coated on the both sides of above-mentioned single-layer composite diaphragm by pulling method, then diaphragm is heated in blast oven at 60 Dry at ℃ for 8 hours, and then dry at 60℃ for 12 hours in a vacuum oven after the solvent evaporates. In this way, a double-sided mod...

technical field

[0001] The invention belongs to the field of lithium-sulfur batteries, in particular to a multilayer composite separator for lithium-sulfur batteries. Background technique

[0002] In today's society, while the rapid economic development enables people to obtain ample material life, the energy crisis and environmental pollution problems are increasingly perplexing the survival of human beings. In this severe situation, the development of new green energy and renewable energy, as well as the corresponding energy conversion and storage technologies are urgent problems to be solved by current scientific and technological workers. Due to the current problems, new energy vehicles and other electronic devices emerged as the times require. However, the lithium-ion batteries currently in circulation in the market have low energy density and cannot meet the high energy density requirements of new electrical equipment. It is imperative to develop a new power supply sy...

Examples

Embodiment 1

[0033] Weigh 5g of PVDF and 95g of NMP to prepare a PVDF solution with a mass fraction of 5%, then mix titanium oxide ceramic particles with a particle size of 50nm with the PVDF solution to make a slurry, and the mass fraction of the ceramic particles in the slurry is 65%. Coat the uniformly mixed inorganic ceramic slurry on one side of a commercially available polyethylene diaphragm, then dry the diaphragm at 60°C in a blast oven for 8 hours, and then dry it in a vacuum oven at 60°C after the solvent evaporates. After 12 hours, the thickness of the inorganic ceramic layer was measured to be 5 μm.

[0034] The PVDF of 8g is taken by weighing, is dissolved in NMP, and preparation PVDF content is 8% solution, and the slurry that obtains is coated on the both sides of above-mentioned single-layer composite diaphragm by pulling method, then diaphragm is heated in blast oven at 60 ℃ drying for 8 hours, after the solvent evaporates, then drying in a vacuum oven at 60 ℃ for 12 hours...

Embodiment 2

[0036] Sulfur-carbon composite (sulfur loading is 70%), acetylene black, and PVDF are prepared by coating the slurry with 7:2:1 on the carbon-coated aluminum foil to prepare the positive electrode, and the metal lithium foil is used as the negative electrode, obtained in Example 1. The diaphragm, the electrolyte uses 0.85M LiN (CF 3 SO 2 ) 2 ,DOL:DME=1:2(V:V),0.3M LiNO 3 , Assemble the CR2016 button battery, and test the cycle performance of the battery. When the battery test temperature is 25°C and the test rate is 0.05C, the first discharge specific capacity of the battery is 1239mAh / g, and the capacity retention rate still reaches 87% after 80 cycles. When the battery test temperature is 25°C and the test rate is 0.08C, the first discharge specific capacity of the battery is 1165mAh / g, and the capacity retention rate still reaches 81% after 80 cycles.

Embodiment 3

[0038] Weigh 5g of PVDF and 95g of NMP to prepare a PVDF solution with a mass fraction of 5%, and then mix ultrafine boron nitride ceramic particles with the PVDF solution to make a slurry, and the mass fraction of the ceramic particles in the slurry is 65%. Coat the uniformly mixed inorganic ceramic slurry on one side of a commercially available polyethylene diaphragm, then dry the diaphragm at 60°C in a blast oven for 8 hours, and then dry it in a vacuum oven at 60°C after the solvent evaporates. After 12 hours, the thickness of the inorganic ceramic layer was measured to be 5 μm.

[0039] The PVDF of taking 10g is dissolved in NMP, and preparation PVDF content is 10% solution, the slurry that obtains is coated on the both sides of above-mentioned single-layer composite diaphragm by pulling method, then diaphragm is heated in blast oven at 60 Dry at ℃ for 8 hours, and then dry at 60℃ for 12 hours in a vacuum oven after the solvent evaporates. In this way, a double-sided mod...