Fire-Resistant Battery Cell with Nonflammable Electrolyte
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current Li-ion batteries face safety concerns due to the flammability of common electrolytes, which exacerbates the issue of uneven Li plating and dendrite formation on the anode, particularly with high-capacity Li metal electrodes, where stable solid-electrolyte interphase (SEI) layers are critical but difficult to form.
Innovation Solution
The introduction of a nonflammable electrolyte, such as triethyl phosphate (TEP), and exposure to O2 to facilitate the formation of a stable SEI layer rich in Li3PO4 and poly-phosphates through electrochemical reduction reactions, enhancing lithium stripping and plating efficiency and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flammable carbonate-based electrolytes are used, then high ionic conductivity and electrochemical performance are achieved, but safety deteriorates due to fire hazards and exacerbated dendrite formation
Solution Approach 1:
The patent changes the chemical composition parameter of the electrolyte from flammable carbonate-based electrolytes to non-flammable phosphate-based electrolytes (specifically TEP - triethyl phosphate). This fundamental parameter change eliminates the fire hazard while maintaining ionic conductivity through the phosphate ester chemistry, directly resolving the safety versus fire hazard contradiction.
Solution Approach 2:
The patent converts the previously harmful interaction between Li metal and electrolyte (which caused unstable SEI and dendrites) into a beneficial process. By using phosphate-based electrolytes, the harmful reactions are transformed into controlled reactions that form stable protective layers (Li3PO4 and poly-phosphate SEI), turning the formerly harmful electrolyte-anode interaction into a protective mechanism.
2Quantity of substance
If Li metal anode is used for high capacity, then energy density is improved, but stability deteriorates due to unstable SEI formation and dendrite growth
Solution Approach 1:
The patent changes the electrolyte composition parameter to phosphate-based chemistry, which fundamentally alters the SEI formation process. Instead of the unstable SEI formed with carbonate electrolytes, the phosphate electrolyte produces stable Li3PO4 and poly-phosphate SEI layers, resolving the contradiction between high capacity and SEI stability.
Solution Approach 2:
The patent creates a composite SEI structure consisting of Li3PO4 and poly-phosphate components on the Li metal anode. This composite material approach provides both the high capacity needed from Li metal and the stability required for practical operation, as the multi-component SEI offers superior mechanical and chemical stability compared to single-component SEI layers.
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 battery cell with improved Coulombic Efficiency, extended cycle life, and enhanced safety by preventing dendrite formation, achieving over 5,000 charging and discharging cycles with 70% capacity retention, and demonstrating compatibility with both Li-O2 and Li-ion battery systems.
Implementation Method 1
exposure to O2 to facilitate the formation of a stable SEI layer rich in Li3PO4 and poly-phosphates through electrochemical reduction reactions
Implementation Method 2
a separator configured to separate the anode and the cathode and permit lithium ion permeability there-through
Data Source
AI summary
The present invention provides a method of making fire-resistant battery cells comprising nonflammable electrolytes, and use thereof.