Composite Electrolyte for Solid-State Battery Ionic Conductivity
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Solution Overview
Problem
Solid-state lithium ion batteries face limitations in ionic conductivity and energy density due to inadequate polymeric electrolyte materials and interfacial impedance between solid components, which impede lithium ion transport and reduce battery performance.
Innovation Solution
A solid-state lithium ion battery design incorporating a cathode with a conductive composite material comprising polyvinylene difluoride (PVdF) and Li1.3Ti1.7Al0.3(PO4)3, along with a lithium salt, to enhance lithium-ion conductivity and mitigate interfacial impedance by using an inorganic ion-conducting material and a polymer to form a composite electrolyte.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymeric solid-state electrolyte materials like PEO are used, then the battery structure is simplified and safety is improved, but ionic conductivity is inadequate for practical power performance
Solution Approach 1:
The patent uses composite solid electrolyte materials combining polymeric matrices (like PEO) with inorganic ion-conducting particles (such as Li1.3Ti1.7Al0.3(PO4)3 or LLZO) to achieve both the safety advantages of solid-state batteries and improved ionic conductivity. The composite structure leverages the mechanical flexibility and safety of polymers while incorporating the high ionic conductivity of inorganic materials.
Solution Approach 2:
The patent modifies the chemical and physical parameters of the polymeric electrolyte by adding lithium salts (such as LiTFSI) and inorganic fillers to enhance ionic conductivity. The composition ratios, molecular weight of polymers, and particle size of inorganic additives are optimized to achieve desired conductivity while maintaining structural integrity.
2Reliability
If thin film structures are used to achieve successful solid-state batteries, then device functionality is achieved, but energy density is reduced
Solution Approach 1:
The patent employs porous or composite electrode structures that maintain adequate thickness for energy storage while ensuring sufficient ionic transport pathways. The porous architecture increases surface area for electrochemical reactions without proportionally increasing volume, thereby maintaining energy density.
3Ease of manufacture
If interfaces among solid components are present, then battery assembly is simplified, but lithium ion transport is limited and impedance increases
Solution Approach 1:
The patent addresses interfacial impedance by modifying the local properties at material interfaces. Surface treatments, buffer layers, or gradient compositions are introduced at electrode-electrolyte interfaces to improve wetting and reduce resistance, while the bulk materials maintain their original advantageous properties.
4Quantity of substance
If lithium metal anode is used, then energy density is dramatically increased, but dendrite formation and thermal runaway risk increase
Solution Approach 1:
The patent introduces a solid nonporous electrolyte as an intermediary barrier between the lithium metal anode and the rest of the battery. This solid electrolyte layer physically prevents dendrite penetration while maintaining ionic conductivity, enabling the safe use of high-capacity lithium metal anodes.
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 composite electrolyte formulation improves lithium-ion conductivity and cycle life, achieving higher energy density and reduced impedance, leading to enhanced battery performance and capacity retention.
Implementation Method 1
an ion-conducting inorganic material... Li1.3Ti1.7Al0.3(PO4)3... improves lithium-ion conductivity
Implementation Method 2
a polymer, which can be non-conducting... PVdF... form a composite electrolyte
Implementation Method 3
an additive salt... lithium salt... source of lithium ions in the solid electrolyte
Data Source
AI summary
An electrode formulation including a polymer, which can be ion-conducting or non-conducting; an ion-conducting inorganic material; a lithium salt; and optionally an additive salt.