Battery Electrolyte Passivation Layer for Manganese Ion Control
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Solution Overview
Problem
Batteries with transition metal positive electrodes and graphite negative electrodes face performance degradation due to manganese ion dissolution at high temperatures, leading to reduced cycling performance and increased self-discharge.
Innovation Solution
Incorporating a lithium-based electrolyte with passivation salts and additives, such as lithium bis(oxalato)borate and vinyl carbonate, which form stable passivation layers on the negative electrode to prevent manganese ion deposition and enhance battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high current draw is applied to the battery, then power output is improved, but temperature increases causing manganese ion dissolution and performance degradation
Solution Approach 1:
A passivation layer is introduced as an intermediary between the negative electrode and the electrolyte containing dissolved manganese ions. This passivation layer acts as a mediator that prevents harmful manganese ion deposition on the negative electrode while allowing lithium ion transport, thus resolving the contradiction between high power output and cycling performance reliability
Solution Approach 2:
The dissolved manganese ions, which are harmful to battery performance, are converted into a beneficial passivation layer through controlled deposition. The passivation layer forms from manganese ions but instead of degrading performance, it protects the negative electrode from further manganese deposition and stabilizes the electrode structure, transforming the harmful effect into a protective mechanism
2Temperature
If high temperature operation is permitted, then battery performance is improved, but manganese ion dissolution increases leading to negative electrode degradation
Solution Approach 1:
The passivation layer serves as a protective intermediary that blocks the direct interaction between high-temperature electrolyte and the negative electrode. This intermediary layer prevents manganese ions from dissolving and depositing on the negative electrode even at elevated temperatures, while still permitting necessary ionic transport for battery operation
3Ease of manufacture
If conventional electrolyte composition is used, then battery cost is reduced, but passivation layer stability deteriorates at high temperature and high current
Solution Approach 1:
The electrolyte is formulated as a composite system containing multiple components including lithium salts, cyclic carbonates, chain carbonates, and passivation agents. This composite electrolyte composition creates a more stable and robust passivation layer compared to conventional single-component electrolytes, maintaining both cost-effectiveness and enhanced stability under high temperature and high current conditions
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 stabilizes the passivation layer, improving cycling performance and reducing self-discharge, thereby enhancing battery performance at high temperature and high current conditions.
Implementation Method 1
At least one of the passivation salts forms a passivation layer on the negative electrode during charge of the battery
Implementation Method 2
The ions can then migrate to the negative electrode where they deposit onto the negative electrode
Implementation Method 3
A battery includes an electrolyte activating a positive electrode and a negative electrode
Implementation Method 4
The ions can then migrate to the negative electrode where they deposit onto the negative electrode
Implementation Method 5
At least one of the passivation additives forms a passivation layer on the negative electrode during discharge of the battery
Data Source
AI summary
The battery includes an electrolyte activating a positive electrode and a negative electrode. The electrolyte includes a plurality of salts in a solvent, one or more passivation salts in the solvent, and one or more passivation additives in the solvent. At least one of the passivation salts forms a passivation layer on the negative electrode during discharge of the battery and includes both lithium and boron. At least one of the salts is an inorganic lithium salt that excludes boron. The solvent includes one or more organic solvents. At least one of the passivation additives forms a passivation layer on the negative electrode during discharge of the battery and is not a salt. The positive electrode has one or more positive active materials that each include a lithium transition-metal oxide and the negative electrodes includes a negative active material selected from a group consisting of lithium metal and graphite.