A highly ionic transference number eutectogel hybrid electrolytes based on spontaneous coupling inhibitor for solid-state lithium metal batteries

Polymer-based solid electrolytes have been extensively studied for solid-state lithium metal batteries to achieve high energy density and reliable security.But,its practical application is severely limited by low ionic conductivity and slow Li+transference.Herein,based on the“binary electrolytes”of poly(vinylidene fluoride-chlorotrifluoroethylene)(P(VDF-CTFE))and lithium salt(LiTFSI),a kind of eutectogel hybrid electrolytes(EHEs)with high Li+transference number was developed via tuning the spontaneous coupling of charge and vacated space generated by Li-cation diffusion utilizing the Li6.4La3Zr1.4Ta0.6O12(LLZTO)dopant.LLZTO doping promotes the dissociation of lithium salt,increases Li+carrier density,and boosts ion jumping and the coordination/decoupling reactions of Li+.As a result,the optimized EHEs-10%possess a high Li-transference number of 0.86 and a high Li+conductivity of 3.2×10–4 S·cm–1 at room temperature.Moreover,the prepared EHEs-10%composite solid electrolyte presents excellent lithiumphilic and compatibility,and can be tested stably for 1,200 h at 0.3 mA·cm–2 with assembled lithium symmetric batteries.Likewise,the EHEs-10%films match well with high-loading LiFePO4 and LiCoO2 cathodes(>10 mg·cm–2)and exhibit remarkable interface stability.Particularly,the LiFePO4//EHEs-10%//Li and LiCoO2//EHEs-10%//Li cells deliver high rate performance of 118 mAh·g–1 at 1 C and 93.7 mAh·g–1 at 2 C with coulombic efficiency of 99.3%and 98.1%,respectively.This work provides an in-depth understanding and new insights into our design for polymer electrolytes with fast Li+diffusion.

An ion-percolating electrolyte membrane for ultrahigh efficient and dendrite-free lithium metal batteries

The development of lithium(Li)metal batteries has been severely limited by the formation of lithium dendrites and the associated catastrophic failure and inferior Coulombic efficiency which caused by non-uniform or insufficient Li^(+)supply across the electrode-electrolyte interface.Therefore,a rational strategy is to construct a robust electrolyte that can allow efficient and uniform Li^(+)transport to ensure sufficient Li^(+)supply and homogenize the Li plating/stripping.Herein,we report an ion-percolating electrolyte membrane that acts as a stable Li^(+)reservoir to ensure a near-single Li^(+)transference number(0.78)and homogenizes Li^(+)migration to eradicate dendrite growth,endowing Li//LFP cell with an ultrahigh average Coulombic efficiency(ca.99.97%)after cycling for nearly half of a year and superior cycling stability when pairing with LiCoO_(2) with limited Li amount and LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2).These estimable attributes demonstrate significant potential of utility value for the ion-percolating electrolyte.