Cobalt-Free Cathode Slurry for Air and Moisture Isolation
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Solution Overview
Problem
Lithium-ion batteries with nickel (Ni) and manganese (Mn) elements face issues such as migration, oxidation-reduction reactions, gas production, and self-discharge due to surface interactions with electrolytes and environmental factors, leading to reduced performance and safety concerns, especially at high temperatures.
Innovation Solution
A cobalt-free positive electrode material slurry comprising a cobalt-free positive electrode material, a solvent, a sulfone compound with unsaturated bonds, and an auxiliary agent, which enhances viscosity and provides better air and moisture isolation, reducing impurity generation and improving battery performance and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If nickel and manganese elements are used in positive electrode material, then energy density is improved, but surface migration and oxidation-reduction reactions occur leading to gas production and self-discharge
Solution Approach 1:
The patent introduces a coating layer comprising phosphorus, sulfur, and fluorine elements as an intermediary barrier between the nickel-manganese positive electrode material and the electrolyte. This coating layer prevents direct contact and chemical reactions, thereby eliminating gas production and self-discharge while preserving the high energy density benefits of nickel-manganese materials.
2Reliability
If metaphosphate is added to enhance electronic conductivity, then first Coulombic efficiency and gram capacity improve, but contact surface area with electrolyte increases potentially causing more side reactions
Solution Approach 1:
The patent combines multiple protective elements (phosphorus, sulfur, fluorine) into a single integrated coating layer that simultaneously provides electronic conductivity enhancement and electrolyte isolation. This merged approach achieves the benefits of metaphosphate (conductivity and efficiency) while preventing its harmful side effect (increased electrolyte contact and side reactions).
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The cobalt-free positive electrode material slurry results in lithium-ion batteries with high first discharge capacity, capacity retention rate, and first Coulombic efficiency, along with enhanced safety, as evidenced by improved performance metrics such as discharge capacity above 166 mAh/g and capacity retention rate above 57% after 500 cycles.
Implementation Method 1
a sulfone compound with unsaturated bonds, and an auxiliary agent, which enhances viscosity
Implementation Method 2
provides better air and moisture isolation, reducing impurity generation
Data Source
AI summary
Disclosed herein are a cobalt-free positive electrode material slurry, a preparation method therefor and an application thereof. The cobalt-free positive electrode material slurry comprises a cobalt-free positive electrode material, a solvent, a sulfone compound containing unsaturated bonds and an auxiliary agent. When the total parts by weight of the cobalt-free positive electrode material and the auxiliary agent are 100 parts, the parts by weight of the solvent are 25-40 parts, and the parts by weight of the sulfone compound containing the unsaturated bond are 1-7 parts. A positive electrode pole piece formed by the cobalt-free positive electrode material slurry may better isolate air and moisture and protect the cobalt-free positive electrode material of a core component. The lithium ion battery formed thereby has a relatively high first discharge capacity, capacity retention rate and first Coulombic efficiency, and is relatively safe.