Double-coated composite solid lithium manganate material and preparation method thereof

Abstract

The invention discloses a double-coated composite solid-state lithium manganate material and a preparation method thereof. The preparation method comprises the following steps of mixing and sinteringa lithium salt, a titanium salt, an aluminum salt and a phosphate raw material to obtain a solid-state electrolyte lithium titanium aluminum phosphate (Li <1+x> Al <x> Ti <2-x> (PO4) 3 (LATP); addingLATP, single crystal lithium manganate, a graphene oxide aqueous solution and zirconium oxide balls into a sand mill to be fully ground, nanocrystallizing the LATP and attaching the LATP to the surface of the lithium manganate, and meanwhile, coating the lithium manganate with graphene oxide; and after drying, reducing the graphene oxide into graphene at a high temperature in a hydrogen atmosphereto obtain the solid electrolyte and the graphene double-coated lithium manganate positive electrode material. According to the method, the consistency and repeatability of the material are ensured, the manufacturing cost is low, the solid electrolyte can inhibit the dissolution of manganese, the graphene blocks the reaction between the electrolyte and the positive electrode material, and the cycle performance and the high-temperature performance are improved.

Description

technical field

[0001] The invention relates to the field of lithium ion batteries, in particular to a preparation method of a double-coated composite solid lithium manganate material and a lithium ion battery. Background technique

[0002] The specific capacity of positive electrode materials is the most important factor affecting the energy density and cycle life of lithium-ion batteries. Among the four common systems of lithium cobaltate, ternary materials, lithium iron phosphate and lithium manganate, lithium manganate has abundant resources and low cost. It is an ideal cathode material for power batteries due to its advantages of low cost, no heavy metals, high voltage, good safety, and good rate performance. However, its poor cycle performance and high temperature stability greatly limit its industrialization. The main reason is that lithium manganese oxide generates more Mn at the end of discharge. 3+ , prone to the Jahn-Teller effect, the disproportionation of triva...

Examples

Embodiment 1

[0027] Weigh 2.91g of lithium carbonate, 8.22g of titanium dioxide, 0.93g of alumina, 20.89g of ammonium dihydrogen phosphate and 32.95g of ethanol, put them into a 100ml ball mill jar, the ball-to-material ratio is 2: 1, ball mill for 4 hours, mix well, and dry Then place it in a muffle furnace at 750°C for 12 hours to generate Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 . Add 200g of single crystal lithium manganate, 2.4g of LATP, and 80g of graphene oxide aqueous solution into a sand mill with a ball-to-material ratio of 10:1, grind for 20 minutes, dry and place in a tube furnace, and feed in hydrogen with a content of 5% The argon gas mixture was kept at 900°C for 12 hours to prepare a solid electrolyte and graphene double-coated lithium manganate cathode material.

[0028]The obtained lithium manganate cathode material was mixed with sp, CNTs and PVDF at a mass ratio of 95: 1: 2: 2, NMP was added to stir the mixture into a cathode slurry, and evenly coated on aluminum foil, dried...

Embodiment 2

[0030] Weigh 3.78g of lithium carbonate, 15.51g of titanic acid, 5.06g of aluminum nitrate, 15.59g of diammonium hydrogen phosphate and 39.94g of ethanol, put them into a 100ml ball mill jar, the ball-to-material ratio is 2: 1, and ball mill for 12 hours to mix well, bake After drying, place it in a muffle furnace at 650°C for 12 hours to generate LATP. Add 200g single crystal lithium manganese oxide, 6.0g LATP, and 80g graphene oxide aqueous solution into a sand mill with a ball-to-material ratio of 10:1, grind for 40 minutes, dry and place in a tube furnace, and feed 1% hydrogen The argon gas mixture was kept at 700°C for 4 hours to prepare a solid electrolyte and graphene double-coated lithium manganate cathode material.

[0031] The obtained lithium manganate cathode material was mixed with sp, CNTs and PVDF at a mass ratio of 95: 1: 2: 2, NMP was added to stir the mixture into a cathode slurry, and evenly coated on aluminum foil, dried at 80°C for 6 hours, 120 ℃ vacuum d...

Embodiment 3

[0033] Take by weighing 1.89g lithium hydroxide, 8.22g titanium dioxide, 2.43g aluminum nitrate, 20.89g ammonium dihydrogen phosphate and 33.43g ethanol, put into 100ml ball mill jar, ball material ratio is 2: 1, ball mill 4 hours fully mix, bake After drying, place it in a muffle furnace at 800°C for 4 hours to generate LATP. Add 200g single crystal lithium manganese oxide, 3.0g LATP, and 80g graphene oxide aqueous solution into a sand mill with a ball-to-material ratio of 10:1, grind for 8 minutes, dry and place it in a tube furnace, and feed it with 5% hydrogen The argon gas mixture was kept at 900°C for 12 hours to prepare a solid electrolyte and graphene double-coated lithium manganate cathode material.

[0034] The obtained lithium manganate cathode material was mixed with sp, CNTs and PVDF at a mass ratio of 95: 1: 2: 2, NMP was added to stir the mixture into a cathode slurry, and evenly coated on aluminum foil, dried at 80°C for 6 hours, 120 ℃ vacuum drying for 12 hou...

technical field

[0001] The invention relates to the field of lithium ion batteries, in particular to a preparation method of a double-coated composite solid lithium manganate material and a lithium ion battery. Background technique

[0002] The specific capacity of positive electrode materials is the most important factor affecting the energy density and cycle life of lithium-ion batteries. Among the four common systems of lithium cobaltate, ternary materials, lithium iron phosphate and lithium manganate, lithium manganate has abundant resources and low cost. It is an ideal cathode material for power batteries due to its advantages of low cost, no heavy metals, high voltage, good safety, and good rate performance. However, its poor cycle performance and high temperature stability greatly limit its industrialization. The main reason is that lithium manganese oxide generates more Mn at the end of discharge. 3+ , prone to the Jahn-Teller effect, the disproportionation of triva...

Examples

Embodiment 1

[0027] Weigh 2.91g of lithium carbonate, 8.22g of titanium dioxide, 0.93g of alumina, 20.89g of ammonium dihydrogen phosphate and 32.95g of ethanol, put them into a 100ml ball mill jar, the ball-to-material ratio is 2: 1, ball mill for 4 hours, mix well, and dry Then place it in a muffle furnace at 750°C for 12 hours to generate Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 . Add 200g of single crystal lithium manganate, 2.4g of LATP, and 80g of graphene oxide aqueous solution into a sand mill with a ball-to-material ratio of 10:1, grind for 20 minutes, dry and place in a tube furnace, and feed in hydrogen with a content of 5% The argon gas mixture was kept at 900°C for 12 hours to prepare a solid electrolyte and graphene double-coated lithium manganate cathode material.

[0028]The obtained lithium manganate cathode material was mixed with sp, CNTs and PVDF at a mass ratio of 95: 1: 2: 2, NMP was added to stir the mixture into a cathode slurry, and evenly coated on aluminum foil, dried...

Embodiment 2

[0030] Weigh 3.78g of lithium carbonate, 15.51g of titanic acid, 5.06g of aluminum nitrate, 15.59g of diammonium hydrogen phosphate and 39.94g of ethanol, put them into a 100ml ball mill jar, the ball-to-material ratio is 2: 1, and ball mill for 12 hours to mix well, bake After drying, place it in a muffle furnace at 650°C for 12 hours to generate LATP. Add 200g single crystal lithium manganese oxide, 6.0g LATP, and 80g graphene oxide aqueous solution into a sand mill with a ball-to-material ratio of 10:1, grind for 40 minutes, dry and place in a tube furnace, and feed 1% hydrogen The argon gas mixture was kept at 700°C for 4 hours to prepare a solid electrolyte and graphene double-coated lithium manganate cathode material.

[0031] The obtained lithium manganate cathode material was mixed with sp, CNTs and PVDF at a mass ratio of 95: 1: 2: 2, NMP was added to stir the mixture into a cathode slurry, and evenly coated on aluminum foil, dried at 80°C for 6 hours, 120 ℃ vacuum d...

Embodiment 3

[0033] Take by weighing 1.89g lithium hydroxide, 8.22g titanium dioxide, 2.43g aluminum nitrate, 20.89g ammonium dihydrogen phosphate and 33.43g ethanol, put into 100ml ball mill jar, ball material ratio is 2: 1, ball mill 4 hours fully mix, bake After drying, place it in a muffle furnace at 800°C for 4 hours to generate LATP. Add 200g single crystal lithium manganese oxide, 3.0g LATP, and 80g graphene oxide aqueous solution into a sand mill with a ball-to-material ratio of 10:1, grind for 8 minutes, dry and place it in a tube furnace, and feed it with 5% hydrogen The argon gas mixture was kept at 900°C for 12 hours to prepare a solid electrolyte and graphene double-coated lithium manganate cathode material.

[0034] The obtained lithium manganate cathode material was mixed with sp, CNTs and PVDF at a mass ratio of 95: 1: 2: 2, NMP was added to stir the mixture into a cathode slurry, and evenly coated on aluminum foil, dried at 80°C for 6 hours, 120 ℃ vacuum drying for 12 hou...