The Fabrication of in Situ Polymerization of 1,3-Dioxlane/Poly(vinyl alcohol)/Polyethylenimine Quasi-Solid Polymer Electrolyte for a Lithium Metal Battery Operated at Low Temperatures

Abstract

The development of a high-performance electrolyte that can work at low temperatures is critical for expanding the application of lithium metal batteries. However, most of the present electrolytes suffer from low ionic conductivity and poor interface contact at low temperatures. Herein, an ∼21 μm-thick quasi-solid polymer electrolyte is prepared by in situ polymerization of 1,3-dioxlane (PDOL) within the poly(vinyl alcohol)/ polyethylenimine (PVA/PEI) nanofiber skeleton that contains −NH− groups. The generated hydrogen bond interactions between PDOL and PVA/PEI nanofiber, together with the inherently strong mechanical strength of the nanofiber, confer quasi-solid polymer electrolyte (QSE@PVA/PEI) the tensile strength of 12.1 MPa. Meanwhile, the interactions also interfere with the chain arrangement of PDOL and efficiently enhance the chain mobility, giving QSE@PVA/PEI a remarkable ionic conductivity of 3.29 × 10 −5 S cm −1 and a high Li + transference number of 0.437 at −60 °C. As a result, the Li/QSE@PVA/PEI/Li cell can operate over 1500 h without obvious polarization at 0.2 mA cm −2 and −20 °C. Moreover, the NCM523/QSE@PVA/PEI/ Li cell can stably cycle at −20 °C, delivering a high discharge capacity of 106.7 mAh g −1 over 600 cycles at 0.2 C, which outperforms most reported electrolytes. Even at −40 °C, a modest discharge capacity of 75.2 mAh g −1 is obtained at 0.2 C.

In situ polymerization of solid-state polymer electrolytes for lithium metal batteries: a review

“…PI nonwovens have many three-site pore structures with pore sizes ranging from 1 to 6 μm, and this unique structure contributes to the excellent wettability of the solid electrolyte before polymerization. Zhang et al 169 prepared porous poly(vinyl alcohol)/polyethyleneimine (PVA/PEI) by electrospinning with abundant –NH-functional groups. Thin quasi-solid polymer electrolytes (QSE@PVA/PEI) were prepared by filling the pores with DOL precursor solution for in situ ring-opening polymerization (Fig.…”

2023 Pioneers in Energy Research: Shizhang Qiao

“…This novel electrolyte demonstrates a high ionic conductivity, a large electrochemical stability window, and a remarkable lithium-ion transference number. Zhang et al 50 proposed another improvement of lithium batteries. They developed a quasi-solid polymer electrolyte by in situ polymerization of 1,3-dioxlane (PDOL) within the poly(vinyl alcohol)/polyethylenimine (PVA/PEI) nanofiber skeleton.…”

Disassociating Lithium Salts in Deep Eutectic Solvents and Inhibiting Aluminum Corrosion for Low-Temperature Lithium–Metal Batteries

“…Metallic lithium (Li) is rightly cited as the anode in rechargeable batteries owing to its high theoretical specific capacity (3860 mAh g –1 ) and the most negative electrode potential (−3.04 V vs SHE). − Unfortunately, its electrochemical performance is severely limited under low-temperature conditions. − Electrolytes, acting as the “blood” of lithium-ion (Li-ion) batteries, are sensitive to temperature . Commercial electrolytes contain ethylene carbonate (EC) components to solvate Li and benefit the formation of solvent-separated ion pair (SSIP) for rapid ion migration at room temperature.…”