Ultrathin PEO Solid Electrolyte With CN Support and HNT@TMP Filler
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Solution Overview
Problem
Current lithium ion batteries face limitations in energy density, cycle life, and safety due to the semi-crystalline nature of PEO-based solid electrolytes, which restrict lithium ion migration, mechanical strength, and flammability, with phosphorus flame retardants causing incompatibility with metal anodes.
Innovation Solution
A preparation method for a flame-retardant ultrathin PEO-based solid electrolyte using a multifunctional filler HNT@TMP and porous cellulose nanopaper (CN) to enhance mechanical strength and thermal stability, while encapsulating trimethyl phosphate in halloysite nanotubes to prevent side reactions and promote lithium ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If PEO-based solid electrolyte is used, then easy processing and good lithium salt solubility are achieved, but limited lithium ion migration and insufficient mechanical strength occur
Solution Approach 1:
The patent uses a composite structure consisting of PEO-based solid electrolyte combined with porous cellulose nanopaper (CN) support layer. The CN layer provides mechanical strength and structural stability, while the PEO layer maintains good lithium salt solubility and ion conductivity. This composite approach resolves the contradiction between ease of processing and reliability by combining materials with complementary properties.
2Quantity of substance
If PEO-based solid electrolyte is used, then good lithium salt solubility is achieved, but insufficient mechanical strength to inhibit lithium dendrites occurs
Solution Approach 1:
The porous cellulose nanopaper (CN) support layer provides high mechanical strength and structural rigidity, enabling the electrolyte to effectively inhibit lithium dendrite growth. Meanwhile, the PEO-based electrolyte layer maintains excellent lithium salt solubility. The composite structure allows both requirements to be satisfied simultaneously.
Solution Approach 2:
The patent applies different material properties to different parts of the electrolyte structure: the CN support layer provides mechanical strength where needed for dendrite inhibition, while the PEO electrolyte layer provides lithium salt solubility in the ion-conducting region. This local differentiation of material functions resolves the contradiction.
3Quantity of substance
If PEO solid electrolyte thickness is reduced, then high energy density is achieved, but mechanical strength and safety are compromised
Solution Approach 1:
The porous cellulose nanopaper (CN) support layer provides exceptional mechanical strength and thermal stability, allowing the overall electrolyte thickness to be greatly reduced while maintaining structural integrity and safety. The thin composite electrolyte enables high energy density batteries without compromising mechanical strength.
Solution Approach 2:
The patent successfully creates an ultrathin electrolyte membrane with thickness significantly reduced from conventional sizes. The CN support layer acts as a flexible yet strong substrate that maintains mechanical integrity even at ultrathin dimensions, enabling high energy density while ensuring safety.
4Object-affected harmful factors
If phosphorus flame retardant is added to improve flame retardance, then flame retardant efficiency is improved, but incompatibility with metal anodes occurs
Solution Approach 1:
The porous cellulose nanopaper (CN) support layer acts as an intermediary barrier between the phosphorus flame retardant and the metal anode. It allows the flame retardant to be present in the electrolyte for safety while preventing direct contact and harmful side reactions with the lithium metal anode, thus resolving the incompatibility issue.
Solution Approach 2:
The patent localizes the flame retardant function within the electrolyte matrix while maintaining a distinct interface with the metal anode through the CN support layer. This spatial separation allows flame retardance to be achieved without compromising anode compatibility.
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 method achieves improved electrochemical performance, mechanical strength, and flame retardance, facilitating high energy density and safety in lithium batteries by inhibiting combustion and accelerating lithium ion transmission.
Implementation Method 1
the mechanical strength of the ultrathin PEO electrolyte is ensured through porous cellulose nanopaper (CN) with excellent mechanical flexibility and thermal stability
Implementation Method 2
in the thermal runaway process of a battery, due to the increase of temperature, the flame retardant in the HNT gasifies and captures free radicals in the combustion process of polymer, thus effectively inhibiting the combustion of the polymer electrolyte
Implementation Method 3
A flame retardant trimethyl phosphate (TMP) is encapsulated in a halloysite nanotube (HNT), which inhibits a side reaction generated between the flame retardant dissolved directly in an electrolyte and a lithium metal negative electrode
Implementation Method 4
The unique charge distribution structure of 'positive inside and negative outside' of the HNT can promote the dissociation of lithium salt and produce more freely conductible lithium ions, thereby accelerating the transmission of the lithium ions in the PEO-based electrolyte
Data Source
AI summary
A preparation method of a flame-retardant ultrathin PEO-based solid electrolyte is disclosed. The method includes the following steps: preparing a CN support layer; synthesizing a flame retardant-loaded multifunctional filler: HNT@TMP; mixing and stirring PEO, LiTFSI, and HNT@TMP in a certain ratio in acetonitrile to obtain PEO-based solid electrolyte slurry; coating both sides of the CN support layer obtained in step S1 with the PEO-based solid electrolyte slurry obtained in step S3, and performing drying; and performing hot pressing to obtain a PEO-based solid electrolyte. By adopting the preparation method of the flame-retardant ultrathin PEO-based solid electrolyte, the electrochemical performance and flame retardance of a PEO-based solid polymer electrolyte are improved through a multifunctional flame-retardant filler (HNT@TMP), and the mechanical strength of the ultrathin PEO electrolyte is ensured through porous cellulose nanopaper (CN) with excellent mechanical flexibility and thermal stability, whereby the development of high energy density is facilitated.