Li-Al-Si Anode and Carbon-Coated Cathode for Thermal Battery Performance
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Solution Overview
Problem
Current thermal batteries, particularly those using lithium-silicon alloy powder and FeS2 with eutectic electrolytes, fail to meet the demands for high power and energy density required by advanced applications, such as defense and space exploration, due to limited discharge capacity, power, and voltage, while also presenting hazardous manufacturing challenges.
Innovation Solution
The development of anode and cathode compositions featuring metallic lithium alloys, lithium alloying additives, and carbon-coated metal fluorides, which enhance specific discharge capacity, power, and energy, along with improved manufacturing safety through the use of materials like Li—Si, Li—Al, LiCoO2, and carbon-coated FeF3, integrated with a molten salt electrolyte system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium-silicon alloy powder and FeS2 are used as anode and cathode materials, then the battery provides long shelf life and stable performance, but the discharge capacity and power density are limited
Solution Approach 1:
The patent changes the chemical composition parameters of the anode material by introducing lithium aluminum silicon alloy (Li-Al-Si) instead of conventional lithium silicon alloy (Li-Si). This parameter change in material composition enables higher discharge capacity while maintaining the long shelf life characteristic of thermal batteries, as the Li-Al-Si alloy provides both improved electrochemical performance and stability during storage.
Solution Approach 2:
The patent employs composite anode materials consisting of lithium aluminum silicon alloy combined with other components to achieve synergistic effects. This composite approach allows the battery to simultaneously attain high discharge capacity from the Li-Al-Si alloy and long shelf life from the stable composite structure, resolving the contradiction between performance and reliability.
2Ease of manufacture
If conventional anode materials are used, then manufacturing is simpler, but the process becomes hazardous due to very reactive components
Solution Approach 1:
The patent introduces aluminum as an intermediary element in the lithium aluminum silicon alloy anode material. This intermediary component moderates the reactivity of lithium, reducing the hazardous nature of the anode materials during manufacturing while maintaining the electrochemical performance. The aluminum acts as a buffer that simplifies handling and manufacturing processes compared to pure lithium or lithium silicon alloys.
3Power
If the battery operates at higher voltage, then the power density increases, but the energy required for high power applications is not sufficient
Solution Approach 1:
The lithium aluminum silicon alloy anode material provides multi-functionality by simultaneously contributing to both high power density and high energy density. The unique composition enables the material to deliver high current at elevated voltages (power) while also storing substantial energy, making it universally suitable for high power applications that require both attributes.
Solution Approach 2:
The patent changes the electrochemical parameters of the anode material through the Li-Al-Si composition, which enables operation at higher voltages and currents. This parameter change in the material's electrochemical properties allows the battery to achieve both high power density and high energy density, satisfying the dual requirements for high power applications.
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
These compositions result in thermal batteries with significantly increased specific discharge capacity, power, and energy density, while ensuring safer manufacturing processes, making them suitable for demanding applications like defense and space exploration.
Implementation Method 1
an internal pyrotechnic charge is activated and generates sufficient heat to elevate the battery temperature over melting temperature of the molten salt electrolyte
Implementation Method 2
elevate the battery temperature over melting temperature of the molten salt electrolyte
Implementation Method 3
anode compositions comprising a metallic lithium; a lithium alloy; and a lithium alloying additive
Implementation Method 4
cathode compositions comprising a carbon-coated metal fluoride
Data Source
AI summary
Disclosed herein are compositions and methods of making such compositions, for making lithium-containing anodes and cathodes. Disclosed are batteries comprising such anodes and/or cathodes, and uses for such batteries. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.