CN-122025551-A - Positive electrode plate, preparation method thereof and battery

Abstract

The invention provides a positive electrode plate, a preparation method thereof and a battery, wherein the positive electrode plate comprises a current collector, an undercoat and a positive electrode active material layer which are sequentially arranged along the thickness direction; the primer layer comprises a ceramic material and a conductive agent, the ceramic material comprises at least one of Al 2 O 3 、ZrO 2 , and the positive electrode active material layer comprises a lithium manganate material. The battery has higher cycle life and better cycle stability under the high-temperature working condition.

Inventors

• WAN FENG
• WANG WENXING
• LI XUEFA

Assignees

• 扬州纳力新材料科技股份有限公司

Dates

Publication Date

20260512

Application Date

20260309

Claims (10)

1. 1. The positive electrode plate comprises a current collector, an undercoat layer and a positive electrode active material layer which are sequentially arranged along the thickness direction; The primer layer comprises a ceramic material and a conductive agent, wherein the ceramic material comprises at least one of Al 2 O 3 、ZrO 2 ; The positive electrode active material layer includes a lithium manganate material.
2. 2. The positive electrode sheet of claim 1, wherein M is doped in the lithium manganate material, and the ionic radius of M is larger than that of Mn 3+ .
3. 3. The positive electrode sheet of claim 2, wherein M comprises Dy.
4. 4. The positive electrode sheet according to claim 3, wherein the preparation method of the lithium manganate material comprises the following steps: LiOH H 2 O、MnSO 4 、H 2 O 2 、Dy 2 O 3 is mixed and then reacted for 9-11 hours at a temperature of 110-130 ℃, wherein MnSO 4 ：Dy 2 O 3 = (45-60): 1 is calculated according to the mass ratio.
5. 5. The positive electrode sheet according to claim 4, wherein the amount of MnSO 4 and H 2 O 2 used in the preparation method of the lithium manganate material is as follows, and MnSO 4 ：H 2 O 2 = (3-5): (2-4) is calculated according to a molar ratio.
6. 6. The positive electrode sheet according to claim 1, wherein the ceramic material comprises Al 2 O 3 、ZrO 2 , and Al 2 O 3 ：ZrO 2 = (0.5-1.5) 1 in terms of mass ratio.
7. 7. The positive electrode sheet according to claim 1, wherein the conductive agent comprises conductive carbon black, and the conductive agent is ceramic material= (4-6): 4 in terms of mass ratio.
8. 8. The positive electrode sheet according to claim 1, wherein the single-layer thickness of the undercoat layer is 3to 5 μm.
9. 9. The preparation method of the positive electrode plate according to any one of claims 1 to 8, which is characterized by comprising the following steps: And dissolving the binder in a solvent, and then sequentially adding the ceramic material, the dispersing agent and the conductive agent to mix to prepare the primer paste.
10. 10. A battery comprising the positive electrode sheet according to any one of claims 1 to 8 or the positive electrode sheet produced by the production method according to claim 9.

Description

Positive electrode plate, preparation method thereof and battery Technical Field The invention belongs to the technical field of lithium ion batteries, and particularly relates to a positive pole piece, a preparation method thereof and a battery. Background The lithium manganese oxide (LiMn 2O4, abbreviated as lithium manganate LMO) is used as one of important parts of the battery anode active material, and has application prospect in the fields of high energy density and sustainable energy storage due to higher working voltage, rich raw materials and environmental friendliness. However, the LMO material is susceptible to Jahn-Teller distortion and disproportionation of manganese ions during high temperature cycling, resulting in crystal structure destruction and manganese dissolution, and further causing volume change and stress concentration of the positive electrode active material layer during cycling of the battery, thereby accelerating pulverization of the active material, resulting in rapid capacity decay, which severely limits long-term use of the LMO material under high temperature conditions. Disclosure of Invention The invention provides a positive pole piece, a preparation method thereof and a battery. According to one aspect of the invention, there is provided a positive electrode sheet comprising a current collector, an undercoat layer, and a positive electrode active material layer arranged in this order in a thickness direction, the undercoat layer comprising a ceramic material comprising at least one of Al 2O3、ZrO2 and a conductive agent, and the positive electrode active material layer comprising a lithium manganate material. According to the invention, at least one of Al 2O3、ZrO2 is used as a ceramic material, and under a high-temperature working condition, the bottom coating can bear the positive electrode active material layer, so that side reactions such as oxidation of the current collector and dissolution of manganese in the lithium manganate material are effectively reduced, and the cycle stability of the battery under the high-temperature working condition is improved. The lithium manganate material can be at least one selected from unmodified lithium manganate, surface-coated modified lithium manganate and bulk-doped modified lithium manganate. Preferably, the lithium manganate material is doped with M, and the ionic radius of M ions is larger than that of Mn 3+. The lithium manganate material is doped with M ions with the ionic radius larger than Mn 3+, so that Jahn-Teller distortion can be effectively inhibited, and the lattice structure stability of the lithium manganate material is improved, thereby reducing capacity attenuation of the battery in a high-temperature circulation process and improving the circulation stability of the battery under a high-temperature working condition. Preferably, M comprises Dy. When dysprosium is doped in the lithium manganate material, jahn-Teller distortion can be further restrained, dy 3+ entering the lattice structure of the lithium manganate material plays a role in anchoring the lattice structure through the bonding action of oxygen atoms in the lattice structure, mn 3+ is difficult to deviate from the lattice structure and perform disproportionation reaction, and the structural stability of the lithium manganate material at high temperature can be effectively improved, so that the stability of the battery in high-temperature circulation is improved. Preferably, the preparation method of the lithium manganate material comprises the following steps of mixing LiOH-H 2O、MnSO4、H2O2、Dy2O3, and then reacting for 9-11 hours at the temperature of 110-130 ℃, wherein the mass ratio of MnSO 4 to Dy 2O3 = (45-60) 1. When the mass ratio of MnSO 4 to Dy 2O3 is regulated and controlled to be (45-60): 1, the doping amount of Dy element in the lithium manganate material can be effectively regulated and controlled, and the initial discharge capacity and the structural stability of a pole piece prepared from the lithium manganate material are effectively considered, so that the lithium manganate material can be kept stable in high-temperature circulation, and the cycle life of the battery at high temperature is further prolonged. Preferably, in the preparation method of the lithium manganate material, the using amount of MnSO 4 and H 2O2 is satisfied, and according to the mole ratio, mnSO 4：H2O2 = (3-5): (2-4). Preferably, the ceramic material comprises Al 2O3、ZrO2, and Al 2O3：ZrO2 = (0.5-1.5) 1 in terms of mass ratio. By using Al 2O3 and ZrO 2 as ceramic materials and regulating and controlling the feeding proportion of Al 2O3 and ZrO 2, the uniform distribution of current can be promoted under the high-temperature working condition, the heat in the pole piece can be timely dredged, meanwhile, the oxidation of the current collector at high temperature can be effectively reduced, the condition of increasing internal resistance is relieved, and the two materi