Positive Electrode Plate Polymer Electrolyte for Low-Resistance Interfaces
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Solution Overview
Problem
The solid-solid interface between the positive electrode active material and the solid electrolyte in solid-state batteries exhibits poor lithium-conducting and electricity-conducting performance, leading to high internal resistance and poor interfacial contact, which affects the cycling performance of the battery.
Innovation Solution
A positive electrode plate comprising a positive electrode active material, a conductive agent, and a polymer electrolyte with a polymer containing specific structural units, such as polyether borate, aluminate, or phosphate segments, is used to enhance lithium ion conductivity and reduce porosity, forming a continuous lithium-conducting and electricity-conducting network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a solid polymer electrolyte is used in a high voltage positive electrode plate, then energy density is improved, but the electrolyte is oxidized and decomposed, destroying the lithium-conducting and electricity-conducting network
Solution Approach 1:
The patent introduces fluorinated groups into the polymer electrolyte structure, changing the chemical composition parameters to increase oxidation resistance. The fluorinated polymer electrolyte maintains lithium ion conductivity while resisting oxidation at high voltages, thereby preserving the lithium-conducting network and enabling high energy density applications.
Solution Approach 2:
The patent creates a composite structure by incorporating fluorinated polymer segments into the electrolyte matrix. This composite approach combines the high ion conductivity of traditional polymer electrolytes with the oxidation resistance of fluorinated groups, achieving both high energy density and network stability.
2Productivity
If the porosity of the positive electrode plate is increased to improve lithium ion transmission, then lithium-conducting performance is improved, but internal resistance increases and cycling performance deteriorates
Solution Approach 1:
The patent applies local quality by creating a gradient structure where the fluorinated polymer electrolyte concentrates at the solid-solid interface regions. This localized distribution improves lithium ion transmission at critical interfaces without requiring high overall porosity, thereby maintaining low internal resistance and good cycling performance.
Solution Approach 2:
The fluorinated polymer electrolyte acts as an intermediary substance that fills and optimizes the interface regions between solid particles. It mediates lithium ion transport across the solid-solid interfaces, improving transmission efficiency without creating the high porosity that would harm cycling performance.
3Ease of manufacture
If conventional polymer electrolytes are used to reduce manufacturing complexity, then ease of manufacture is improved, but interfacial contact is poor and cycling performance is poor
Solution Approach 1:
The patent modifies the chemical parameters of the polymer electrolyte by introducing fluorinated groups, which change the surface properties and interfacial interactions. This chemical modification improves wetting and contact at solid-solid interfaces while maintaining the simplicity of polymer electrolyte processing methods.
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 solution improves the cycling performance and energy density of solid-state batteries by reducing internal resistance and enhancing lithium ion transmission, while maintaining high voltage resistance and stability.
Implementation Method 1
the polymer electrolyte includes a polymer and a lithium salt; and the polymer includes a repeated unit represented by the following formula 1... enhancing lithium ion conductivity
Implementation Method 2
a porosity on a surface of the positive electrode plate is low... the polymer includes a repeated unit represented by the following formula 1
Data Source
AI summary
Disclosed are a positive electrode plate and a lithium-ion secondary battery containing the positive electrode plate. In the present disclosure, a polymer electrolyte prepared from a polymer that is different from a polymer used in the conventional technology, and the solid electrolyte, having not only a binding function but also a lithium-conducting function, may replace a binder and a solid electrolyte in an existing electrode plate, so that transmission performance of lithium ions can be effectively improved, and an internal resistance of a solid-state battery can be reduced. In addition, a porosity of a positive electrode plate containing the solid electrolyte is low. This effectively improves energy density and cycling performance of the solid-state battery. The positive electrode plate containing the solid electrolyte may be applied to a battery system having high energy density, thereby broadening a disclosure range of the positive electrode plate.