Solid-State Battery Li-V-Al-Ti-P-O Composition Reduces Internal Resistance
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Solution Overview
Problem
All solid-state lithium ion secondary batteries face challenges in reducing internal resistance due to lower lithium ion conductivity and higher internal resistance compared to batteries with organic electrolytic solutions, as the use of different metal components in the polyanion compounds for electrode active materials and solid electrolytes hinders improved conductivity.
Innovation Solution
The use of a Li—V—Al—Ti—P—O compound with specific content ratios for both electrode active materials and solid electrolytes, where high vanadium content improves charge capacity and high aluminum and titanium content enhance lithium ion conductivity, ensuring the same elements are used for both active materials and electrolytes to improve conductivity between layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different metal components are used in polyanion compounds for electrode active materials and solid electrolytes, then material composition flexibility is improved, but lithium ion conductivity between layers deteriorates
Solution Approach 1:
The patent applies homogeneity by using the same metal components (Al and Ti) in both the electrode active material (Li3V2(PO4)3) and the solid electrolyte (Li1.4Al0.2Ti0.2Si0.2P0.8O4). This compositional consistency creates a homogeneous interface between layers, improving lithium ion conductivity while maintaining material flexibility through controlled variations in content ratios.
2Power
If internal resistance is reduced, then output current is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies merging by combining the optimization of electrode active material and solid electrolyte into a unified approach. By coordinating the metal component ratios between Li3V2(PO4)3 and Li1.4-Alx-Tiy-Siz-P1-x-yO4, the patent reduces internal resistance and improves output current while avoiding the need for separate complex manufacturing processes.
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
This approach results in a significant reduction of internal resistance, enhancing the battery's output current and charge/discharge efficiency by improving lithium ion conductivity between electrode active material and solid electrolyte layers.
Implementation Method 1
all solid-state lithium ion secondary batteries generally have lower lithium ion conductivity than organic electrolytic solutions
Implementation Method 2
a solid electrolyte layer provided between the pair of electrode layers
Data Source
AI summary
An active material layer containing a compound represented by a general formula (1): LiaVbAlcTidPeO12 (1), where a, b, c, d, and e in the general formula (1) are numbers satisfying 0.5≤a≤3.0, 1.20<b≤2.00, 0.01≤c<0.06, 0.01≤d<0.60, and 2.80≤e≤3.20; and a solid electrolyte layer containing a compound represented by a general formula (2): LifVgAlhTiiPjO12 (2), where f, g, h, i, and j in general formula (2) are numbers satisfying 0.5≤f≤3.0, 0.01≤g<1.00, 0.09<h≤0.30, 1.40<i≤2.00, and 2.80≤j≤3.20.