All-solid-state battery carbon particle conductivity
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Solution Overview
Problem
All-solid-state batteries with solid electrolytes face challenges in achieving low internal resistance and high discharge capacity, particularly due to the low electron conductivity of materials like Li3V2(PO4)3, which limits their performance compared to batteries using liquid electrolytes.
Innovation Solution
Incorporating carbon particles with an average interplanar spacing d002 of less than 0.342 nm in the positive and negative electrode active material layers, which enhances electron conductivity and reduces internal resistance by increasing the contact area and crystallinity, allowing for smoother electron transfer and higher discharge capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Li3V2(PO4)3 is used as active material in all-solid-state batteries, then the battery can achieve solid-state construction without liquid electrolyte leakage, but the electron conductivity becomes low and internal resistance increases
Solution Approach 1:
The patent combines Li3V2(PO4)3 active material with carbon particles to create a composite electrode structure. The carbon particles form a conductive network within the active material matrix, providing electron transport pathways while maintaining the solid-state battery's structural stability and preventing electrolyte leakage.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the electrode by controlling the carbon particle characteristics (size distribution, morphology, concentration) to optimize electron conductivity. By adjusting these parameters, the internal resistance is reduced while maintaining the benefits of solid-state construction.
2Power
If conventional carbon particles are added to improve electron conductivity, then conductivity increases, but the internal resistance reduction is insufficient
Solution Approach 1:
The patent specifically controls the carbon particle size distribution (D10, D50, D90 parameters) and morphological parameters to optimize the conductive network formation. This precise parameter control enables more effective electron transport compared to conventional carbon additives, achieving greater internal resistance reduction.
Solution Approach 2:
The patent creates localized conductive regions around Li3V2(PO4)3 particles using carbon particles with specific size and morphology. This local conductive network ensures efficient electron collection at each active material particle interface, thereby reducing overall internal resistance more effectively than uniform carbon distribution.
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 use of carbon particles with specific characteristics in the electrode layers results in a significant decrease in internal resistance and an increase in discharge capacity, improving the overall performance of all-solid-state batteries.
Implementation Method 1
the carbon particles having an average interplanar spacing d002 of smaller than 0.342 (nm) have favorable crystallinity as a graphite structure and cause periodic disarray to a small extent and thereby have high thermal stability and can be easily left in electrodes even in the case of using a process involving after a heat treatment such as sintering. Therefore, a small amount of the carbon particles added make it possible to obtain a high electron conductivity
Data Source
AI summary
An all-solid-state battery having a positive electrode layer including a positive electrode current collector layer and a positive electrode active material layer, a negative electrode layer including a negative electrode current collector layer and a negative electrode active material layer, and a solid electrolyte layer containing a solid electrolyte, and the positive electrode active material layer and the negative electrode active material layer each contain carbon particles having an average interplanar spacing d002 of smaller than 0.342 (nm).