Lithium-ion Battery Vanadium Negative Electrode Gas Suppression
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Solution Overview
Problem
Lithium-ion secondary batteries using phosphate positive electrode materials face issues with low charging/discharging voltage and energy density, as well as gas generation leading to swelling, which affects shape stability.
Innovation Solution
A lithium-ion secondary battery design incorporating a positive electrode with vanadium phosphate active material, specifically Lia(M)b(PO4)cFd (M=VO or V), and an electrolyte containing 5 to 30 ppm of hydrofluoric acid, along with a negative electrode containing 1 to 100 ppm of vanadium, to suppress gas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If phosphate positive electrode materials (LiFePO4, LiCoPO4, LiNiPO4) are used to achieve high voltage or high safety, then charging/discharging voltage or thermal stability is improved, but gas generation occurs leading to battery swelling and shape instability
Solution Approach 1:
A specific electrolyte composition acts as an intermediary between the phosphate positive electrode and the negative electrode. The electrolyte contains 5-30 ppm hydrofluoric acid and 0.01-5 wt% cyclic carbonate, which modifies the interface chemistry to suppress gas generation while maintaining the high voltage and thermal stability benefits of phosphate materials.
Solution Approach 2:
The invention changes the chemical parameters of the electrolyte by precisely controlling the concentration of hydrofluoric acid (5-30 ppm) and cyclic carbonate (0.01-5 wt%). These parameter changes transform the electrolyte's interaction with the electrode materials, suppressing gas generation mechanisms while preserving the electrochemical performance of phosphate positive electrodes.
2Power
If phosphate positive electrode materials are used to achieve high charging/discharging voltage, then voltage is improved, but gas generation occurs leading to battery swelling
Solution Approach 1:
The modified electrolyte serves as a mediator that enables high voltage operation without gas generation. The specific composition (5-30 ppm HF and 0.01-5 wt% cyclic carbonate) creates a stable interface that prevents the electrochemical reactions leading to gas formation, allowing phosphate materials to operate at their high voltage potential safely.
Solution Approach 2:
By adjusting the electrolyte parameters (HF concentration and cyclic carbonate content), the invention creates optimal conditions for high voltage operation. These parameter changes suppress parasitic reactions that would otherwise generate gas, enabling sustained high voltage charging and discharging without battery swelling.
3Ease of manufacture
If conventional electrolyte composition is used with phosphate positive electrode materials, then manufacturing simplicity is maintained, but gas generation and shape instability occur
Solution Approach 1:
The invention introduces specific parameter ranges for electrolyte composition (5-30 ppm HF, 0.01-5 wt% cyclic carbonate) that can be integrated into existing manufacturing processes. These parameter changes maintain relative manufacturing simplicity while dramatically improving shape stability by suppressing gas generation during battery operation.
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 battery effectively suppresses gas generation, maintaining shape stability and potentially improving charging/discharging performance by using vanadium phosphate and optimizing electrolyte and electrode compositions.
Implementation Method 1
an electrolyte containing 5 to 30 ppm of hydrofluoric acid
Implementation Method 2
a negative electrode containing 1 to 100 ppm of vanadium
Data Source
AI summary
The lithium-ion secondary battery includes a positive electrode containing an active material made of a compound including lithium and a transition metal; an electrolyte containing 5 to 30 ppm of hydrofluoric acid; and a negative electrode containing 1 to 100 ppm of vanadium.