Interhalogen Cathode Electrolytes for High-Capacity Battery Cycling
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Solution Overview
Problem
Current lithium-ion batteries face limitations such as low energy density and high costs of cathode materials like cobalt and nickel, and existing halogen cathode batteries require significant conductive additives or solubility of chloride in the electrolyte, hindering their widespread application.
Innovation Solution
An interhalogen cathode battery is developed using an electrolyte formulation with two chemically distinct halogen-containing compounds (HCC-1 and HCC-2) that reversibly form an interhalogen compound within the cathode during charging, allowing for efficient energy storage and continued cycling, with a lithium-containing anode and a carbon material cathode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lithium-ion batteries use metal oxide or metal phosphate-based cathode materials, then the batteries have stable structure and good cycling performance, but the energy density is low and the cost is high due to cobalt and nickel materials
Solution Approach 1:
The patent changes the electrochemical parameters of the cathode by using halogen-containing compounds instead of conventional metal oxides or phosphates. The halogen compounds enable higher specific capacity (422 mAh/g for iodine-based chemistry) compared to conventional cathode materials, directly increasing energy density while maintaining structural stability through the intercalation mechanism
Solution Approach 2:
The patent employs composite cathode structures combining carbon materials with halogen-containing compounds. This composite approach allows the carbon matrix to provide structural stability and conductivity while the halogen compounds contribute high capacity, achieving both reliability and high energy density simultaneously
2Quantity of substance
If lithium metal batteries use halogen cathodes with electrochemical conversion of halide ions to iodine, then the specific capacity is 211 mAh/g I, but 40% or more by weight conductive additive is required in the cathode
Solution Approach 1:
The patent introduces an intermediary mechanism where halogen-containing compounds intercalate into the carbon cathode structure. This intermediary approach allows electron transport through the carbon matrix itself without requiring excessive conductive additives, as the carbon structure provides inherent conductivity pathways while accommodating the halogen compounds
Solution Approach 2:
The halogen-containing compounds are pre-incorporated into the carbon cathode structure before battery operation. This preliminary action ensures that the compounds are already in optimal positions for electrochemical conversion, eliminating the need for additional conductive additives to facilitate electron transport during cycling
3Quantity of substance
If lithium metal batteries use interhalogen chemistry converting iodine to mixed or interhalogen species, then the specific capacity increases to ~422 mAh/g I or ~360 mAh/g I-Cl, but solubility of chloride as a starting material in the electrolyte is required
Solution Approach 1:
The patent extracts the chloride from the electrolyte environment and places it directly into the cathode structure as a solid halogen-containing compound. This extraction eliminates the solubility requirement in the electrolyte while maintaining the high capacity interhalogen chemistry, as the chloride is now part of the solid-state cathode material rather than requiring dissolution in the liquid electrolyte
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 interhalogen cathode battery achieves high specific capacities and efficient energy storage, reducing the need for costly materials and improving performance compared to conventional lithium-ion batteries, making it suitable for various applications including electric vehicles.
Implementation Method 1
HCC-1 and HCC-2 reversibly form an interhalogen compound within the cathode upon battery charge
Implementation Method 2
the electrochemical conversion of iodine (I, iodine oxidation state=−1) to a mixed or interhalogen species such as iodine monochloride (I—Cl, iodine oxidation state=+1)
Implementation Method 3
upon battery discharge, the interhalogen compound dissociates for continued cycling and energy storage
Implementation Method 4
As the LIB is charged and discharged, lithium ions move back and forth between the positive and negative electrodes
Implementation Method 5
lithium ions move back and forth between the positive and negative electrodes through a liquid electrolyte
Implementation Method 6
through a liquid electrolyte
Data Source
AI summary
Three configurations for an interhalogen cathode battery include a lithium-containing anode, a carbon cathode, two chemically distinct halogen-containing compounds (HCC-1 and HCC-2), and an electrolyte formulation with (i) an ionic salt, (ii) >1% by weight of a compound selected from imidazolidinones, N-alkylated ureas, aprotic carbonates, and/or nitriles, and (iii) one or two chemically distinct halogen-containing compounds. In a first configuration, both the carbon cathode and the electrolyte formulation include HCC-1 and HCC-2. In a second configuration, the carbon cathode includes HCC-1 and the electrolyte solution includes HCC-2. In a third configuration, HCC-1 and HCC-2 are present in the electrolyte, but not the cathode. During battery charge, HCC-1 and HCC-2 reversibly form an interhalogen compound within the cathode and during battery discharge, the interhalogen compound dissociates for continued cycling and energy storage.