Sandwich-Structured Composite Polymer Electrolyte Based on PVDF-HFP/PPC/Al-Doped LLZO for High-Voltage Solid-State Lithium Batteries

Abstract

High-performance solid-state lithium-metal batteries (SSLMBs) require solid electrolytes displaying outstanding electrochemical stability, excellent ionic conductivity, and high Li+ ion transference number. On top of these, it should also be compatible with the electrodes applied and functionable under room temperature. To achieve these, a solution-casting technique is proposed herein to prepare a flexible composite polymer electrolyte (CPE), which is equipped with a high ionic conductivity and Li+ ion transference number, concurrently applicable in the construction of high-voltage solid-state Li batteries. The proposed CPE, which is made up of poly(vinylidene difluoride-co-hexafluoropropylene) (PVDF-HFP)/polypropylene carbonate (PPC) blend with an Al-doped Li7La3Zr2O12 (Al-LLZO) filler, was sandwiched between PVDF-HFP/PPC–lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) skin layers with SN plasticizer added. This formulation of PVDF-HFP/PPC/Al-LLZO/LiTFSI/SN was abbreviated as sandwich-PPA in our study. Such configuration permits notable resistance reduction at the electrode–electrolyte interface while suppressing Li dendrite growth throughout the robust charging–discharging process. This can be attributed to the excellent performance of the sandwich composite electrolyte membrane, which promises high ionic conductivity (ca. 4.04 × 10–4 S cm–1) and a high Li+ ion transference number (ca. 0.583) at room temperature. A CR2032 coin cell, which is assembled with Al2O3-C@NCA/Sandwich-PPA/Li, delivered a high specific capacity (186.20 mAh g–1 at 0.1C at room temperature), along with its excellent rate performance and cycle stability (discharge capacity of 126.23 mAh g–1; capacity retention of 80.03% after 100 cycles at a rate of 0.5C at room temperature). This verified the potential of our novelty-formulated solid-state electrolyte to secure excellent performance of SSLMBs.

Solid-state composite electrolytes: turning the natural moat into a thoroughfare

“…63 P(VDF-HFP) was also used to construct the skin layer layers in a sandwich-structured electrolyte design. 64 The blending of P(VDF-HFP) and polypropylene carbonate (PPC) can increase the ionic conductivity and Li + transference number, while the flexible skin layer P(VDF-HFP)/PPC/LiTFSI/SN without Al-doped LLZO (Al-LLZO) filler ensures enhanced interfacial contact with electrodes, which suppresses the Li dendrite growth. This sandwich-structured composite electrolyte exhibits a high ionic conductivity of 4.04 × 10 −4 S cm −1 and a high Li + ion transference number of 0.583 at RT.…”

Poly(Propylene Carbonate)-Based Biodegradable and Environment-Friendly Materials for Biomedical Applications

“…At present, PPC has been extensively used in food packaging [ 7 , 8 ], battery manufacturing [ 9 , 10 ], agricultural mulch films [ 11 ] and cushioning foams [ 12 ], etc. In addition, owing to its good biocompatibility and non-toxic degradation products, PPC also holds significant promise for biomedical applications, such as drug carriers [ 13 , 14 ], tissue engineering scaffolds [ 15 , 16 ] and medical dressings [ 17 ].…”

LLZTO Nanoparticle- and Cellulose Mesh-Coreinforced Flexible Composite Electrolyte for Stable Li Metal Batteries

“…To better meet the application-specific requirements of solid-state batteries, the applied solid-state electrolytes should be flexible, thin, highly ion-conductive, chemically stable, and mechanically robust to guarantee the fast Li + transportation inside and the long cycle life of batteries. − Additionally, it is expected to be compatible and form intimate contact with electrodes assembled. Further considering the scalable industrial manufacture, the fabrication process of electrolytes should be simple and energy-saving .…”