Lithium-rich manganese material, positive electrode material for lithium-ion battery, positive plate for lithium-ion battery, lithium-ion battery and preparation method of lithium-ion battery

Abstract

The invention discloses a lithium-rich manganese material, a positive electrode material for a lithium-ion battery, a positive plate for the lithium-ion battery, the lithium-ion battery and a preparation method of the lithium-ion battery and relates to the technical field of lithium-ion batteries. The molecular formula of the lithium-rich manganese material is aLi2MnO3.(1-a)LiNi0.5Mn1.5O4.(1-a)LiNi0.5Mn0.5O2, wherein a is smaller than or equal to 0.3 and greater than or equal to 0.01. The positive electrode material comprises the lithium-rich manganese material; the positive plate is coated with the positive electrode material; an active material of the positive electrode material for the lithium-ion battery is the lithium-rich manganese material; and the active material of a negative electrode material is a SiO / C composite material. According to the lithium-rich manganese material, the defects that an existing positive electrode material is in low specific capacity and low in initialefficiency and an existing negative electrode material is low in coulombic efficiency and poor in cycle performance are relieved. Through the cooperation of the positive electrode material and the negative electrode material, the obtained lithium-ion battery has high specific energy and high security, and the energy density of the battery is greater than 320Wh / kg.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a lithium-rich manganese material, a positive electrode material for a lithium ion battery, a positive electrode sheet for a lithium ion battery, a lithium ion battery and a preparation method thereof. Background technique [0002] An important bottleneck of new energy vehicles is the cruising range of the battery. At present, domestic new energy vehicles still use lithium iron phosphate and ternary lithium batteries, and the cruising range of the models can basically reach 300 kilometers, but the average energy density of the battery system is only 115Wh / Kg. In March 2017, the Ministry of Industry and Information Technology and other four ministries and commissions jointly promulgated the "Action Plan for Promoting the Development of Automotive Power Batteries", pointing out that by 2020, the specific energy of a new lithium-ion power battery will exceed 300Wh / kg; ...

AI Technical Summary

Problems solved by technology

Patent CN102013481A discloses a spherical gradient lithium-rich cathode material xLi 2 MnO 3 ·(1-x)Li[Ni 0.4 co 0.2 mn 0.4 ]O 2 (0.1≤x≤0.4), the specific capacitance of the first discharge is 242mAh / g, and the specific capacity after 50 cycles is 221mAh / g, with the defects of irreversible capacity for the first time, low Coulombic efficiency, and poor cycle stability

Patent CN107123793A discloses a layered lithium-rich manganese-based material Li 1.2 Ni 0.13 co 0.13 mn 0.54 o 2 The preparation method of the lithium-rich manganese-based positive electrode material has a specific capacity of 180mAh / g after 600 charge-discharge cycles at a rate of 1C. Poor, voltage drops during cycling, etc., seriously affect the application of lithium-rich manganese batteries

In addition, these are only half batteries (cathode material / metal lithium), and have not yet been made into full batteries for application

[0005] On the other hand, for the negative electrode of the current lithium-ion power battery, the high-capacity silicon negative electrode material is mainly used, and the theoretical specific capacity of the silicon-based material reaches 4200mAh / g. There is a large volume effect in the process, and the volume expansion rate is >300%, which leads to the pulverization and shedding of the material during the charge and discharge process, resulting in poor cycle performance of the battery

[0006] Therefore, although the lithium-ion battery composed of the above positive and negative electrode materials has a high specific energy density in theory, in practical applications, due to some shortcomings of the material itself, the first-time efficiency of the battery is low, the cycle performance is poor, and it is easy to Inflation, poor safety performance, etc., difficult to practical application

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