Ni-Rich Positive Electrode Mixture for Low-Viscosity Dense Cathodes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing positive electrode mixtures for secondary batteries face challenges in maintaining low viscosity over time, especially when containing high proportions of Ni, which affects the formation of high-density electrodes and initial discharge capacity utilization rates, particularly at low temperatures.
Innovation Solution
A positive electrode mixture comprising polyvinylidene fluoride (PVdF), a fluorine-containing copolymer with vinylidene fluoride and tetrafluoroethylene units, and specific additives such as diketone compounds, amine compounds, organophosphorus compounds, and oxalato complex compounds, which helps in maintaining low viscosity and enhancing adhesion to the current collector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a positive electrode mixture containing high proportion of Ni is used to increase discharge capacity, then the initial discharge capacity utilization rate is improved, but the viscosity of the mixture increases significantly over time
Solution Approach 1:
The patent changes the chemical composition parameters of the binder system by incorporating specific additives (diketone compounds, amine compounds, organophosphorus compounds, or oxalato complex compounds) into the PVdF-based binder. These additives modify the molecular interactions and prevent aggregation, thereby maintaining low viscosity over time while preserving high Ni content for improved discharge capacity.
2Ease of manufacture
If the viscosity of the positive electrode mixture is reduced to improve electrode density, then the manufacturing process becomes easier, but the adhesion to current collector may be compromised
Solution Approach 1:
The patent creates a composite binder system consisting of PVdF as the base polymer combined with specific additives (diketone, amine, organophosphorus, or oxalato complex compounds). This composite structure provides dual functionality: the PVdF ensures adhesion to the current collector, while the additives reduce viscosity and improve flowability, enabling easy electrode formation without compromising bonding strength.
3Quantity of substance
If high-density positive electrodes are formed to increase energy density, then the battery capacity is improved, but the low-temperature output characteristic deteriorates
Solution Approach 1:
The patent modifies the binder system composition by adding specific compounds that prevent polymer aggregation and maintain molecular mobility. This allows the electrode to achieve high density through improved packing while the modified binder maintains flexibility and ionic conductivity at low temperatures, preserving output characteristics.
Data Source
AI summary
A positive electrode mixture containing a polyvinylidene fluoride (A); a fluorine-containing copolymer (B) containing vinylidene fluoride unit and tetrafluoroethylene unit; a positive electrode active material (C) represented by the general formula (C): LiyNi1-xMxO2, wherein x is 0.01≤x≤0.7, y is 0.9≤y≤2.0, and M represents a metal atom (excluding Li and Ni); and an additive (D). Also disclosed is a positive electrode formed from the positive electrode mixture and a secondary battery including the positive electrode.