Layer-Structured Composite Solid-State Electrolyte with a Li_1.3Al_0.3Ti_1.7(PO₄)₃-Coated Separator for High-Voltage Lithium Metal Batteries by In Situ Polymerization

Abstract

The poor interfacial contact between solid-state electrolytes (SSEs) and electrodes, which hinders the applications of solid-state batteries (SSBs), could be improved by in situ polymerization. However, the limited electrochemical window and insufficient mechanical strength of in situ-polymerized electrolytes make them unable to match high-voltage cathodes and inhibit lithium dendrites. Here, a layered organic–inorganic composite solid-state electrolyte structure is designed by introducing a Li1.3Al0.3Ti1.7(PO4)3 (LATP)-coated polyethylene separator and fluoroethylene carbonate (FEC) into in situ-polymerized 1,3-dioxolane (DOL). The high-voltage stable fluoride-rich cathode–electrolyte interface formed in situ by FEC widens the electrochemical window of the composite solid-state electrolyte. In addition, the LATP coating layer inhibits the growth of lithium dendrites and increases the Li-ion conductivity by reacting with FEC to generate FEC derivatives. The Li/LiCoO2 battery exhibits good cycling and rate performance with a cutoff voltage of 4.3 V at room temperature. It provides a simple and practical solution to improve the performance of high-voltage lithium metal batteries based on in situ polymerization.

Regulating Conductive Copolymerization Networks in the Polymer Electrolyte for High-Performance Quasi-Solid-State Lithium–Metal Batteries

“…In addition, Figure S1 presents that the polarization voltage of the Li|PPA1|Li symmetric battery is approximately 60 mV for 130 h at 0.05 mA cm –2 . Consequently, these results confirm further that PPA10 has good lithium plating/stripping behavior in regulating Li + flux deposition, and it can well prevent the growth of Li dendrites . Furthermore, SEM analysis was applied to examine dendrite growth on the Li anode surface in Li||Li symmetric cells with two PPA x electrolyte samples at 0.05 mA cm –2 after 10 cycles, and the results are shown in Figure f,g.…”

In Situ Solid-State DETFPi-PDOL Electrolyte and Its Impact on the Interfaces and Performance of NCM811||Li Batteries

“…However, PDOL lacks sufficient oxidation resistance, and its interfacial compatibility with high-voltage cathodes (cutoff voltage ≥4.2 V, such as NCM cathode) is poor. , Constructing a uniform and stable CEI layer on the surface of the cathodes can significantly improve the PDOL/cathode interfacial compatibility. Guo and co-workers used triphenylphosphine (TPP) to construct a stable CEI layer on the surface of the NCM cathode, achieving the stable cycling of PDOL-EC/DEC/DMC electrolyte for 100 times in NCM622||Li battery; Li and co-workers introduced fluoroethylene carbonate (FEC) and hexamethylene diisocyanate (HDI) into PDOL to construct a stable interface under high voltage, getting the cycling performance of LiCoO 2 ||Li batteries at 4.2 V improved; Sun and co-workers used aluminum isopropoxide (AIP) as an interfacial additive to improve the interfacial stability in PDOL/NCM811 and achieved stable cycling of NCM811||Li batteries at 4.3 V. Presently, one of the problems with PDOL system is, although the additives used can only achieve single interfacial modification, it cannot simultaneously improve the stability of PDOL at cathode/anode interfaces to further enhance the performance of high-voltage lithium metal batteries.…”