Solid electrolytes reinforced by infinite coordination polymer nano-network for dendrite-free lithium metal batteries

As the demand for high energy-density and safe Li-based batteries, the development of composite solid polymer electrolytes (CSPEs) with high ionic conductivity and high electrochemical stability are significant. Herein, the amorphous infinite coordination polymer (ICP) nano-network of Ce-coordinate polyphenol ellagic acid (EACe(2)) is introduced into PEO matrix to achieve highly endurable Li metal batteries (LMBs). Different from conventional metal-organic frameworks (MOFs) with discrete crystalline grains, ICP network with high interconnectivity and self-assembly capability enables the better penetration effect and multi-scale interaction of filler in PEO. EACe(2) nano-filler promotes the improvement of ionic conductivity and Li-ion transference number of CSPEs, as well as the construction of robust solid-electrolyte interphase (SEI) with the concentration of LiF, Li2O and Li2S, leading to ultrastable and kinetically favorable Li/Li cells with dendrite-mitigated cycling over 8800 h. The low interfacial resistances (16 Omega cm(2) and 20.5 Omega cm(2) for CSPE-EACe(2)/Li and CSPE-EACe(2)/LiFePO4 respectively) can achieve highly reversible Li/LiFePO4 cells (with capacities of 102.6 mAh g(-1) after 2000 cycles at 0.5 C and 103.2 mAh g(-1) after 1200 cycles at 1 C). This CSPE-EACe(2) membrane also enables the tolerance of high-voltage cathode (LiNi0.8Co0.1Mn0.1O2, up to 4.3 V), room temperature operation, and ultrathin thickness (25-mu m-thick).

Automated summary

Introducing Ce-coordinate ellagic acid nano-network into PEO matrix improves the performance of composite solid polymer electrolytes, achieving high conductivity and stability, ultimately enhancing the performance of lithium metal batteries.