Anionic Electrochemical Cells Eliminate Metallic Lithium
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Solution Overview
Problem
Current lithium-based electrochemical cells face limitations in achieving high specific energies, safety, and stability due to the use of metallic lithium, which poses safety risks and restricts operating voltages and cycle life.
Innovation Solution
Development of anionic electrochemical cells using anion charge carriers that eliminate the need for metallic lithium, with novel active electrode materials and electrolyte compositions enabling higher specific energies, stable discharge rates, and enhanced safety through the use of fluoride ion charge carriers and host materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If metallic lithium is used in electrochemical cells, then high specific energy can be achieved, but safety risks and stability deteriorate
Solution Approach 1:
The patent removes metallic lithium from the electrochemical cell system and replaces it with lithium ion host materials (such as graphite, lithium titanate, or lithium phosphate) that can reversibly insert and release lithium ions. This extraction of the problematic metallic lithium while retaining the beneficial lithium ion transport mechanism resolves the contradiction between high specific energy and safety/stability
Solution Approach 2:
The patent changes the operational parameters of the electrochemical cell by using host materials with different lithium ion insertion potentials and kinetics. This allows optimization of both energy density and safety through selection of appropriate host materials with suitable electrochemical properties, resolving the contradiction between specific energy and reliability
2Productivity
If conventional lithium-ion batteries are used, then good device performance is achieved, but cycle life is limited
Solution Approach 1:
The patent employs composite electrode structures combining lithium ion host materials with conductive additives and stable matrix materials. This composite approach maintains good device performance through enhanced electron conductivity while significantly improving cycle life through structural stability and reduced degradation during repeated cycling
Solution Approach 2:
The patent uses host materials with inherent structural stability and buffer capacities that preemptively cushion against degradation mechanisms. The host materials are selected to accommodate volume changes and stress during lithium ion insertion/extraction, preventing structural collapse and extending cycle life before degradation can occur
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 anionic electrochemical cells achieve higher specific energies, extended cycle life, and improved safety compared to conventional lithium-ion batteries, with operating voltages exceeding 3.5 V and a cycle life of over 500 cycles, while maintaining stability and safety.
Implementation Method 1
an electrolyte provided between the positive electrode and the negative electrode, wherein the electrolyte is capable of conducting anion charge carriers
Implementation Method 2
the positive electrode and the negative electrode are capable of reversibly exchanging the anion charge carriers with the electrolyte during charging or discharging of the electrochemical cell
Data Source
AI summary
The present invention provides electrochemical cells capable of good electronic performance, particularly high specific energies, useful discharge rate capabilities and good cycle life. Electrochemical cells of the present invention are versatile and include primary and secondary cells useful for a range of important applications including use in portable electronic devices. Electrochemical cells of the present invention also exhibit enhanced safety and stability relative to conventional state of the art primary lithium batteries and lithium ion secondary batteries. For example, electrochemical cells of the present invention include secondary electrochemical cells using anion charge carriers capable of accommodation by positive and negative electrodes comprising anion host materials, which entirely eliminate the need for metallic lithium or dissolved lithium ion in these systems.