Prelithiated Polymer Electrolyte Membrane for High-Capacity Li-Ion Storage
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Solution Overview
Problem
Conventional solid-state lithium-ion batteries are limited by low energy density due to the type of cathode materials used, with conventional cathodes having high cell potentials but low specific battery capacity, and existing prelithiation methods in liquid electrolytes pose safety risks.
Innovation Solution
A prelithiated polymer electrolyte membrane composed of a polyoxide-polysulfide copolymer network is used, which is formed by deep discharging in a specific voltage range to store excess lithium ions, enhancing ion conduction and storage capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional cathode materials (NMC, LiCoO2, LiFePO4) are used in solid-state batteries, then high cell potential is achieved, but specific battery capacity is limited to only 160-170 mAh/g
Solution Approach 1:
The polymer electrolyte membrane is prelithiated by deep discharging the battery in a voltage range of -0.5 V to 5.0 V before normal operation. This preliminary action stores excess lithium ions in the polymer electrolyte network, creating a reservoir that can supplement lithium ion supply during discharge, thereby enabling the battery to achieve both high cell potential and high specific battery capacity
Solution Approach 2:
The patent changes the voltage operating range to -0.5 V to 5.0 V for deep discharging, which is outside the conventional operating range. This parameter change enables the polymer electrolyte membrane to store excess lithium ions effectively, transforming the electrolyte from a passive ion conductor to an active energy storage component that enhances specific battery capacity
2Quantity of substance
If liquid electrolyte is used for prelithiation, then lithium ion storage is achieved, but safety risks occur due to electrolyte boiling and leakage
Solution Approach 1:
The patent changes the electrolyte phase from liquid to solid polymer, and operates at controlled temperatures below the decomposition point of the polymer electrolyte membrane. This parameter change eliminates the safety risks associated with liquid electrolyte boiling and leakage while maintaining lithium ion storage capability through the solid polymer matrix
Solution Approach 2:
The patent uses a composite polymer electrolyte membrane comprising a polyoxide and a polysulfide. This composite material structure provides both the lithium ion storage capability and the thermal stability needed for safe operation, combining the benefits of different polymer components to achieve both high lithium ion capacity and enhanced safety
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 prelithiated polymer electrolyte membrane significantly increases the energy density of solid-state lithium-ion batteries to 400-500 Wh/kg, providing a stable and safe method for lithium ion storage.
Implementation Method 1
solid-state batteries have been developed that use a solid or polymer electrolyte to conduct lithium ions between the anode and cathode
Implementation Method 2
extra storage capacity of lithium ions through coordination bonding of dissociated lithium cations with ether oxygen or nucleophilic amines within the polymer electrolyte network
Data Source
AI summary
An energy storage device is provided that includes a first electrode, a second electrode, and a polymer electrolyte membrane disposed between the first electrode and the second electrode. The polymer electrolyte membrane includes a copolymer network including a polyoxide and a polysulfide. The polymer electrolyte membrane is prelithiated by deep discharging of the battery of in a voltage range of −0.5 V to 5.0 V such that the polymer electrolyte membrane after deep discharging includes additional lithium ions stored therein as compared with prior to deep discharging.