Quasi-Solid Polymer Electrode for High-Loading Alkali Metal Batteries
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Solution Overview
Problem
Current lithium-ion batteries face limitations in achieving high gravimetric and volumetric energy densities, power density, and are plagued by safety issues due to low active material mass loading, dendrite formation, and flammability, which hinder their application in electric vehicles and portable devices.
Innovation Solution
The development of quasi-solid polymer electrodes with high active material mass loading, deformable, and shape-conformable batteries, utilizing a cathode with 30-95% cathode active material, 5-40% electrolyte, and 0.01-30% conductive additives, forming a 3D network for electrical conductivity, and an anode with similar composition, enabling electrodes thicker than 200 μm and higher energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If Li metal is used as anode material to achieve high theoretical capacity, then energy density is improved, but dendrite formation occurs causing safety issues
Solution Approach 1:
The patent changes the physical state parameter of the electrolyte from liquid to gel-form, which fundamentally alters the interface between electrolyte and Li metal anode. This parameter change suppresses dendrite formation by providing a more uniform Li deposition morphology while maintaining high energy density through the use of Li metal anode.
Solution Approach 2:
The patent creates a composite electrolyte system combining liquid electrolyte components with polymer gel matrix (using compounds like LiPF6, LiBF4 in conjunction with polymers such as polyacrylonitrile, polyvinylidene fluoride). This composite structure provides both the ionic conductivity needed for high energy density and the mechanical stability required to prevent dendrite-related safety issues.
2Reliability
If graphite-based anodes are used to improve safety, then dendrite formation is reduced, but specific capacity decreases significantly
Solution Approach 1:
The patent changes the anode material parameter from graphite (intercalation compound) to Li metal (metallic state), achieving a theoretical capacity increase from 372 mAh/g to 3,860 mAh/g. The safety concern is simultaneously addressed through the gel electrolyte modification that enables safe Li metal operation.
3Power
If conventional liquid electrolytes are used to achieve good ionic conductivity, then power density is improved, but flammability increases causing safety risks
Solution Approach 1:
The patent develops a composite electrolyte system combining liquid electrolyte components (providing ionic conductivity for power density) with gel-forming polymers (providing flame retardancy). The gel matrix entraps the liquid electrolyte, maintaining ion transport pathways while suppressing flammability through the polymer network structure.
Solution Approach 2:
The gel-forming polymer acts as an intermediary medium between the liquid electrolyte and the external environment. It mediates the contradiction by allowing ionic conduction (inherited from liquid electrolyte) while providing flame resistance (inherited from polymer gel structure), thus resolving the safety-performance conflict.
4Use of energy by moving object
If electrode thickness is increased to improve energy density, then volumetric energy density is improved, but manufacturing precision becomes more difficult to maintain
Solution Approach 1:
The patent changes the electrode morphology parameter from thin rigid layers to thick flexible gel-form structures. This parameter change enables electrodes thicker than 200 μm to be manufactured with acceptable uniformity, as the gel matrix provides self-leveling properties and flexibility during assembly, accommodating thickness variations without compromising electrochemical performance.
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
This approach results in lithium or sodium batteries with unprecedented high energy and power densities, improved safety through dendrite suppression, and enhanced cycle life, making them suitable for compact, high-performance energy storage applications.
Implementation Method 1
the conductive additive, containing conductive filaments, forms a 3D network of electron-conducting pathways such that the quasi-solid electrode has an electrical conductivity from about 10−6 S/cm to about 300 S/cm
Implementation Method 2
about 5% to about 40% by volume of a first electrolyte containing an alkali salt dissolved in a solvent
Data Source
AI summary
Provided is an alkali metal cell comprising: (a) a quasi-solid cathode containing 30% to 95% by volume of a cathode active material, about 5% to about 40% by volume of a first electrolyte containing an alkali salt dissolved in a solvent and an ion-conducting polymer dissolved, dispersed in or impregnated by a solvent, and about 0.01% to about 30% by volume of a conductive additive wherein the conductive additive, containing conductive filaments, forms a 3D network of electron-conducting pathways such that the quasi-solid electrode has an electrical conductivity from about 10−6 S/cm to about 300 S/cm; (b) an anode; and (c) an ion-conducting membrane or porous separator disposed between the anode and the quasi-solid cathode; wherein the quasi-solid cathode has a thickness from 200 μm to 100 cm and a cathode active material having an active material mass loading greater than 10 mg/cm2.