Amorphous tetratin triphosphate/phosphorus/few-layer graphene negative material for lithium ion batteries and preparation method and application thereof

Abstract

The invention discloses an amorphous tetratin triphosphate / phosphorus / few-layer graphene negative material for lithium ion batteries and a preparation method and an application thereof. The negative material is formed by coating amorphous tetratin triphosphate and phosphorus with a few layers of graphene carbon. The preparation method includes the following steps: mixing and ball-milling tin powder and phosphorus powder to obtain tin triphosphate; and mixing the obtained tin triphosphate with expanded graphite and carrying out ball-milling to obtain the amorphous tetratin triphosphate / phosphorus / few-layer graphene negative material. The negative material prepared in the invention is matched with a lithium iron phosphate positive material, and a lithium ion battery assembled by using the negative material and the lithium ferrous phosphate positive material has the advantages of high capacity and stable cycle and has application potential. The preparation method of the invention has theadvantages of simple process, good repeatability, less time consumption and environment friendliness, and is conducive to actual industrial production.

Description

Technical field

[0001] The invention relates to the technical field of lithium ion battery electrode materials, in particular to an amorphous tetratin phosphide / phosphorus / low-layer graphene negative electrode material for lithium ion batteries, and a preparation method and application thereof. Background technique

[0002] At present, most commercial lithium-ion batteries use graphite materials as negative electrodes, and lithium ions are intercalated into graphite to form interlayer compound Li x C 6 , The theoretical specific capacity is only 372mAh / g. Modification methods such as oxidation, doping, and surface coating can improve the Coulomb efficiency and cycle performance of graphite electrodes. However, due to the inherent characteristics of the material's lithium insertion mechanism, the capacity of graphite materials is still far from the actual demand. Materials such as metal oxides, metal nitrides, and metal phosphides store lithium ions through conversion reactions, a...

Examples

Embodiment 1

[0042] The preparation method of the amorphous tetratin phosphide / phosphorus / small-layer graphene negative electrode material in this embodiment is as follows:

[0043] The first step is ball milling: mixing tin powder and phosphor powder in a molar ratio of 1:3, ball-to-battery ratio of 50:1, ball milling in an argon atmosphere to obtain the ball-milled tin triphosphide. Among them, the ball milling method is planetary ball milling, the ball milling speed is 500 rpm, and the ball milling time is 10 hours.

[0044] The second step of ball milling: the product obtained from the first step of ball milling is mixed with expanded graphite for ball milling with a ball-to-material ratio of 50:1 to obtain an amorphous tetratin phosphide / phosphorus / small-layer graphene negative electrode material. Among them, the mass percentage of expanded graphite in the negative electrode material is 20%, and the ball milling time is 2h.

[0045] The XRD pattern of the amorphous tetratin phosphide / phosph...

Embodiment 2

[0050] In the preparation method of the amorphous tetratin phosphide / phosphorus / small-layer graphene negative electrode material in this embodiment, the other parameters are the same as those in the first embodiment except that the mass percentage of expanded graphite in the negative electrode material is 10%.

[0051] When the negative electrode material prepared in this example is used in the performance test of a lithium ion half-cell, at a current density of 1A / g, the first reversible specific capacity is 1310.2mAh / g, and the first coulombic efficiency is 88.7%. After 100 cycles, it is reversible. The specific capacity can be maintained at 1091.1mAh / g.

Embodiment 3

[0053] In the preparation method of the amorphous tetratin phosphide / phosphorus / small-layer graphene negative electrode material in this embodiment, the other parameters are the same as those in the first embodiment except that the mass percentage of expanded graphite in the negative electrode material is 30%.

[0054] When the negative electrode material prepared in this example is used in the performance test of a lithium-ion half-cell, at a current density of 1A / g, the first reversible specific capacity is 1162.1mAh / g, and the first coulombic efficiency is 88.7%. After 400 cycles, it is reversible. The specific capacity can be maintained at 1101.1mAh / g.

Technical field

[0001] The invention relates to the technical field of lithium ion battery electrode materials, in particular to an amorphous tetratin phosphide / phosphorus / low-layer graphene negative electrode material for lithium ion batteries, and a preparation method and application thereof. Background technique

[0002] At present, most commercial lithium-ion batteries use graphite materials as negative electrodes, and lithium ions are intercalated into graphite to form interlayer compound Li x C 6 , The theoretical specific capacity is only 372mAh / g. Modification methods such as oxidation, doping, and surface coating can improve the Coulomb efficiency and cycle performance of graphite electrodes. However, due to the inherent characteristics of the material's lithium insertion mechanism, the capacity of graphite materials is still far from the actual demand. Materials such as metal oxides, metal nitrides, and metal phosphides store lithium ions through conversion reactions, a...

Examples

Embodiment 1

[0042] The preparation method of the amorphous tetratin phosphide / phosphorus / small-layer graphene negative electrode material in this embodiment is as follows:

[0043] The first step is ball milling: mixing tin powder and phosphor powder in a molar ratio of 1:3, ball-to-battery ratio of 50:1, ball milling in an argon atmosphere to obtain the ball-milled tin triphosphide. Among them, the ball milling method is planetary ball milling, the ball milling speed is 500 rpm, and the ball milling time is 10 hours.

[0044] The second step of ball milling: the product obtained from the first step of ball milling is mixed with expanded graphite for ball milling with a ball-to-material ratio of 50:1 to obtain an amorphous tetratin phosphide / phosphorus / small-layer graphene negative electrode material. Among them, the mass percentage of expanded graphite in the negative electrode material is 20%, and the ball milling time is 2h.

[0045] The XRD pattern of the amorphous tetratin phosphide / phosph...

Embodiment 2

[0050] In the preparation method of the amorphous tetratin phosphide / phosphorus / small-layer graphene negative electrode material in this embodiment, the other parameters are the same as those in the first embodiment except that the mass percentage of expanded graphite in the negative electrode material is 10%.

[0051] When the negative electrode material prepared in this example is used in the performance test of a lithium ion half-cell, at a current density of 1A / g, the first reversible specific capacity is 1310.2mAh / g, and the first coulombic efficiency is 88.7%. After 100 cycles, it is reversible. The specific capacity can be maintained at 1091.1mAh / g.

Embodiment 3

[0053] In the preparation method of the amorphous tetratin phosphide / phosphorus / small-layer graphene negative electrode material in this embodiment, the other parameters are the same as those in the first embodiment except that the mass percentage of expanded graphite in the negative electrode material is 30%.

[0054] When the negative electrode material prepared in this example is used in the performance test of a lithium-ion half-cell, at a current density of 1A / g, the first reversible specific capacity is 1162.1mAh / g, and the first coulombic efficiency is 88.7%. After 400 cycles, it is reversible. The specific capacity can be maintained at 1101.1mAh / g.

Images