In-situ construction of dual lithium-ion migration channels in polymer electrolytes for lithium metal batteries

Abstract

Solid polymer electrolytes (SPEs) are expected to play an important role in high-energy lithium metal batteries (LMBs). Unfortunately, SPEs suffer from inadequate room-temperature ionic conductivity and sluggish interfacial charge transport, which severely limit their widespread applications in LMBs. Herein, we in-situ construct dual lithium-ion migration channels based SPEs by combining ring-opening polymerization of 1,3-dioxolane and solid-state organic ionic plastic crystals. “Coordination-dissociation” with the oxygen atoms in polymer chain segments and fast ion migration inside the organic ionic plastic crystal are two migration modes formed in-situ to synergistically enhance the ionic conductivity and interfacial charge transfer of SPEs. As a result, the in-situ formed poly(1,3-dioxolane)-based solid electrolytes (PDEs) not only afford an integrated battery structure with stabilized electrodes/electrolyte interface but also achieve outstanding oxidation stability, uniform lithium deposition (greater than1200 h under 0.5 mAh cm−2 in symmetric Li cells). Based on PDEs, the Li-LiFePO4 batteries demonstrate excellent cycle stability (almost no capacity decay after 500 cycles under 2C at 25 °C) and a wide operating temperature (-15 ∼ 45 °C). Also, applications of PDEs in Li-LiNi0.6Mn0.2Co0.2O2 batteries further demonstrate the compatibility of PDE with high voltage battery systems. Our study provides a facile and practical approach for creating solid electrolytes that meet both the ionic conductivity and interfacial charge transport requirements for practical solid-state batteries.