Challenges of polymer electrolyte with wide electrochemical window for high energy solid‐state lithium batteries

Abstract

With the rapid development of energy storage technology, solid‐state lithium batteries with high energy density, power density, and safety are considered as the ideal choice for the next generation of energy storage devices. Solid electrolytes have attracted considerable attention as key components of solid‐state batteries. Compared with inorganic solid electrolytes, solid polymer electrolytes have better flexibility, machinability, and more importantly, better contact with the electrode, and low interfacial impedance. However, its low ionic conductivity, narrow electrochemical stability window (ESW), and poor mechanical properties at room temperature limit its development and practical applications. In recent years, many studies have focused on improving the ionic conductivity of polymer electrolytes; however, few systematic studies and reviews have been conducted on their ESWs. A polymer electrolyte with wide electrochemical window will aid battery operation at a high voltage, which can effectively improve their energy density. Moreover, their stability toward lithium metal anode is also important. Therefore, this review summarizes the recent progress of solid polymer electrolytes on the ESW, discusses the factors affecting ESW of polymer electrolytes, and analyzes a strategy to broaden the window from the perspective of molecular interaction, polymer structural design, and interfacial tuning. The development trends of polymer electrolytes with wide electrochemical windows are also presented.

Fluorinated carbon nitride with a hierarchical porous structure ameliorating PEO for high-voltage, high-rate solid lithium metal batteries

“…It determines if an electrolyte can be used in a high-voltage battery. 32 As shown in Fig. 3f, the oxidation potential of 0.1FCN-PEO/LiTFSI is up to 5.2 V, higher than 4.1 V of PEO/LiTFSI.…”

Poly(vinylidene fluoride-co-hexafluoropropylene)-Based Solid Polymer Electrolyte Incorporated with UiO-66 for Lithium Metal Batteries

“…The improved resistivity toward oxidation can be ascribed to the relatively high bandgap value of around 4 eV for UiO-66 fillers. 46,47 When added to the electrolyte, UiO-66 can effectively lower the overall highest occupied molecular orbital (HOMO) value of the polymer electrolytes, thereby inhibiting the oxidation of the electrolyte by positive electrode materials. The Li + transference number is a crucial indicator that reflects the ability of cation transfer and the degree of inhibition of lithium dendrite formation.…”

In Situ Construction Channels of Lithium‐Ion Fast Transport and Uniform Deposition to Ensure Safe High‐Performance Solid Batteries

“…[ 32 ] PMMA has a high LUMO energy level, and PVDF and P(VDF‐HFP) have a lower HOMO energy level. [ 33 ] Therefore, PE with a multi‐dimensional interface can provide fast interface transmission and a wide electrochemical window. The electrochemical stability window of LOPPM PE is stable at 4.80 V, higher than LPP (3.40 V) and LOPP (3.73 V) PEs (Figure 3c).…”