Hexacyanometallate Solid Electrolyte for Stable Lithium-Ion Batteries
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Solution Overview
Problem
Rechargeable lithium-ion batteries face limitations in energy and power density due to the use of unstable liquid or gel organic electrolytes, leading to issues like flammability, instability at elevated temperatures, short circuits, and decay in performance over time, which can be mitigated by replacing these with a solid electrolyte.
Innovation Solution
A solid-state lithium-ion battery design utilizing a hexacyanometallate as the solid electrolyte, which allows for the use of a metallic lithium anode and high-voltage cathode, enhancing energy and power density, and featuring a crystal structure that enables rapid ion diffusion while maintaining electrochemical and chemical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid or gel organic electrolytes are used, then ionic conductivity is achieved, but flammability and instability at elevated temperatures occur
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid/gel to solid, fundamentally altering the material properties to eliminate flammability while maintaining ionic conductivity. The solid electrolyte uses inorganic materials such as sulfides, oxysulfides, or nitrides that are inherently non-flammable and stable at elevated temperatures, thus resolving the contradiction between reliability and harmful factors.
Solution Approach 2:
The patent employs composite solid electrolyte materials combining multiple inorganic components (e.g., sulfides, oxysulfides, nitrides) to achieve both high ionic conductivity and enhanced stability. These composite materials integrate the advantages of different inorganic compounds to simultaneously improve reliability and eliminate flammability issues associated with organic electrolytes.
2Reliability
If solid electrolyte is used, then flammability and stability issues are resolved, but ionic conductivity is reduced compared to liquid electrolytes
Solution Approach 1:
The patent optimizes the crystal structure and composition parameters of solid electrolyte materials to enhance ionic conductivity. By carefully selecting and adjusting the stoichiometry, doping elements, and structural configuration of inorganic solid electrolytes, the patent achieves ionic conductivity levels comparable to or exceeding liquid electrolytes while maintaining the stability advantages of solid materials.
Solution Approach 2:
The patent utilizes porous or layered structures in solid electrolyte materials to facilitate ion transport pathways. The controlled porosity or layered architecture provides efficient channels for lithium ion diffusion, thereby improving ionic conductivity while preserving the solid electrolyte's inherent stability and safety advantages.
3Use of energy by moving object
If metallic lithium anode is used, then energy density is increased, but short circuits due to lithium dendrites occur
Solution Approach 1:
The patent changes the electrolyte parameters from liquid/gel to solid state, which fundamentally alters the mechanical properties and ion transport characteristics. The solid electrolyte's rigid structure physically suppresses lithium dendrite formation by providing mechanical resistance to dendrite penetration, thereby enabling the use of metallic lithium anodes without short circuit risks while maximizing energy density.
Solution Approach 2:
The solid electrolyte acts as an intermediary barrier between the metallic lithium anode and the cathode, preventing direct contact and potential short circuits. The solid electrolyte layer mediates ion transport while providing mechanical protection against dendrite-induced failures, thus enabling safe use of high-capacity metallic lithium anodes.
4Ease of manufacture
If conventional electrolyte is used, then manufacturing is simpler, but decay in energy and power with cycling occurs
Solution Approach 1:
The patent employs composite solid electrolyte materials designed to be chemically inert and electrochemically stable, preventing degradation reactions with electrodes during cycling. These composite materials resist decomposition and maintain structural integrity over thousands of cycles, thereby extending battery life while manufacturing processes are adapted to accommodate the solid material formulation.
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 solid-state battery achieves significantly higher energy and power density compared to conventional batteries, reducing material and manufacturing costs, and demonstrates improved stability and conductivity, making it suitable for high-power applications like electric vehicles.
Implementation Method 1
the hexacyanometallate has an ionic conductivity of about 10−4 S/cm or more
Implementation Method 2
the hexacyanometallate is electrochemically and/or chemically stable when cycled in contact with lithium metal from 0 to 5 V versus Li/Li+
Implementation Method 3
the electrolyte comprises a hexacyanometallate represented by AxPy[R(CN)6-wLw]z... the hexacyanometallate has an ionic conductivity of about 10−4 S/cm or more
Data Source
AI summary
Described here is a solid-state lithium-ion battery, comprising a cathode, an anode, and a solid-state electrolyte disposed between the cathode and the anode, wherein the electrolyte comprises a hexacyanometallate represented by AxPy[R(CN)6-wLw]z, wherein: A is at least one alkali metal cation, P is at least one transition metal cation, at least one post-transition metal cation, and/or at least one alkaline earth metal cation, R is at least one transition metal cation, L is an anion, x, y, and z are related based on electrical neutrality, x>0, y>0, z>0, and 0≤w≤6.