Positive electrode material for lithium ion cell, its preparing method and lithium ion cell

Abstract

The disclosed electrode piece of LiMn2O4 is modified by polymer, which contains functional group of possessing complexation capability with Mn ion. The electrode piece solves issue of difficulties for cladding oxide and thin grains in LiMn2O4 material modified by conductive polymer as well as issue of easy dropping-out clad caused by regrinding. Since effects of complexation and valence bond between polar group of polymer and Mn ions at surfaces of LiMn2O4 grains, oxygenolysis ability of Mn4+ ions for electrolyte and disproportionation degree happened in Mn3+ ions are reduced so as to prevent digestion and migration of lithium ions and increase cyclical stability in high temperature of lithium cell by using LiMn2O4 as positive pole. Features of preparing technique are: simple, feasible and value of industrialization.

Description

technical field

[0001] The invention relates to a lithium ion battery cathode material, in particular to a lithium manganate cathode material. Background technique

[0002] In today's information society, chemical power sources are increasingly valued by people. Among them, lithium-ion batteries have become the energy source of many portable electronic devices and electric vehicle power systems due to their high operating voltage, high energy density, and low environmental pollution. The earliest commercialized lithium-ion battery, that is, the positive electrode material used by most of the current market is LiCoO 2 . Because cobalt resources are scarce, expensive, and harmful to the environment, people are urgently looking for an alternative to LiCoO 2 positive electrode material. Spinel LiMn 2 o 4 Due to the advantages of abundant resources, low price, environmental friendliness and simple synthesis, it has always been a research hotspot, and is considered to be the ...

Examples

Embodiment 1

[0028] Example 1 Functional Polymerization Modified LiMn 2 o 4 Preparation of polymers used in electrode sheets

[0029] The mass ratios of monomer acrylonitrile (AN): monomer N-vinylpyrrolidone (NVP) are respectively 7:2, 5:4, 6:3, 8:7 and 8:5 and fed into the reactor according to 1%, 3%, 5%, and 5% of the total mass of the monomers were added into the initiator AIBN, a certain amount of secondary deionized water was added, and nitrogen gas was passed through for half an hour to remove oxygen in the reaction system. Heating and constant temperature to 65°C, the reaction was terminated after 6 hours of reaction, the prepared polymer was suction filtered, and dried in a vacuum drying oven to obtain a polymer containing functional groups capable of complexing with Mn ions.

Embodiment 2

[0031] The preparation method of the polymer of this embodiment is the same as that of Example 1, and the difference is that acrylamide (AM) monomer is added, and the mass ratio of the reaction raw materials is AN: AM: NVP=5: 4: 2, 6 : 4: 1 and 7: 3: 1, the prepared polymers are all white powdery solids.

Embodiment 3

[0033] In this embodiment, the polymer used to modify the lithium manganate functional material is obtained by copolymerizing the monomer acrylamide (AM) and the monomer cis-2-butenoic anhydride (MAH) in the oil phase, and the mass ratio of the reaction raw materials is The ratio is: AM:MAH=1.3:1.0, and the product is a white solid.

[0034] The preparation method of the functional material polymer used for modifying the lithium manganate electrode is as follows: add 10 parts of cis-2-butenoic anhydride and 30 parts of butanone into the reaction vessel, stir and dissolve, the speed is 100 rpm, and nitrogen gas is introduced into the reaction vessel. Drive oxygen for 1 hour; heat and keep the temperature at 60°C; then add 5 parts of initiator azobisisobutyronitrile; add 13 parts of acrylamide and 50 parts of methyl ethyl ketone in a constant pressure dropping funnel, and add dropwise for 4 hours; react 8 hours are over. A polymer of the above composition was prepared.

technical field

[0001] The invention relates to a lithium ion battery cathode material, in particular to a lithium manganate cathode material. Background technique

[0002] In today's information society, chemical power sources are increasingly valued by people. Among them, lithium-ion batteries have become the energy source of many portable electronic devices and electric vehicle power systems due to their high operating voltage, high energy density, and low environmental pollution. The earliest commercialized lithium-ion battery, that is, the positive electrode material used by most of the current market is LiCoO 2 . Because cobalt resources are scarce, expensive, and harmful to the environment, people are urgently looking for an alternative to LiCoO 2 positive electrode material. Spinel LiMn 2 o 4 Due to the advantages of abundant resources, low price, environmental friendliness and simple synthesis, it has always been a research hotspot, and is considered to be the ...

Examples

Embodiment 1

[0028] Example 1 Functional Polymerization Modified LiMn 2 o 4 Preparation of polymers used in electrode sheets

[0029] The mass ratios of monomer acrylonitrile (AN): monomer N-vinylpyrrolidone (NVP) are respectively 7:2, 5:4, 6:3, 8:7 and 8:5 and fed into the reactor according to 1%, 3%, 5%, and 5% of the total mass of the monomers were added into the initiator AIBN, a certain amount of secondary deionized water was added, and nitrogen gas was passed through for half an hour to remove oxygen in the reaction system. Heating and constant temperature to 65°C, the reaction was terminated after 6 hours of reaction, the prepared polymer was suction filtered, and dried in a vacuum drying oven to obtain a polymer containing functional groups capable of complexing with Mn ions.

Embodiment 2

[0031] The preparation method of the polymer of this embodiment is the same as that of Example 1, and the difference is that acrylamide (AM) monomer is added, and the mass ratio of the reaction raw materials is AN: AM: NVP=5: 4: 2, 6 : 4: 1 and 7: 3: 1, the prepared polymers are all white powdery solids.

Embodiment 3

[0033] In this embodiment, the polymer used to modify the lithium manganate functional material is obtained by copolymerizing the monomer acrylamide (AM) and the monomer cis-2-butenoic anhydride (MAH) in the oil phase, and the mass ratio of the reaction raw materials is The ratio is: AM:MAH=1.3:1.0, and the product is a white solid.

[0034] The preparation method of the functional material polymer used for modifying the lithium manganate electrode is as follows: add 10 parts of cis-2-butenoic anhydride and 30 parts of butanone into the reaction vessel, stir and dissolve, the speed is 100 rpm, and nitrogen gas is introduced into the reaction vessel. Drive oxygen for 1 hour; heat and keep the temperature at 60°C; then add 5 parts of initiator azobisisobutyronitrile; add 13 parts of acrylamide and 50 parts of methyl ethyl ketone in a constant pressure dropping funnel, and add dropwise for 4 hours; react 8 hours are over. A polymer of the above composition was prepared.

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