A Supertough and Highly‐Conductive Nano‐Dipole Doped Composite Polymer Electrolyte with Hybrid Li⁺‐Solvation Microenvironment for Lithium Metal Batteries

Abstract

Achieving solid polymer electrolytes with ceramic‐like fast single‐ion conduction behavior, separator‐required mechanical properties, and good lithium‐dendrite suppression capability is essential but extremely challenging for the practical success of solid‐state lithium‐metal batteries. The key to overcome this long‐standing bottleneck is to rationally design the Li+‐transport microenvironment inside the polymeric ion‐conductors. Herein, the concept of a nano‐dipole doped composite polymer electrolyte (NDCPE) is proposed using surface‐charged halloysite nanotubes (d‐HNTs) as the dopant to achieve a Li+‐transport‐friendly microenvironment in poly(vinylidene fluoride) (PVDF) based quasi‐solid electrolytes. Results show that the d‐HNTs doping can immobilize the anions and help dissociate the lithium salt, which leads to an advanced dynamic Li+‐interface yielding both a high Li+‐transference number (0.75 ± 0.04) and ionic conductivity (0.29 ± 0.04 mS cm−1 @R.T.). Moreover, compared with the commercial separator, the NDCPE thin‐film shows similar toughness, mechanical strength, and puncture resistance, but much superior capability for stabilizing the lithium‐metal anode. To understand the possible doping mechanism, a hybrid Li+‐solvation model combining the surface charges of the nanofiller, absorbed solvent molecules, and absorbed polymer chain unit is proposed and discussed for guiding the future studies on advanced hybrid solid polymer electrolytes.

In-depth exploration of the effect mechanisms of various lithium salt anions in solid-state and liquid lithium metal batteries

“…4g. 38,39 This indicates that a significant portion of TFSI − in the electrolyte is bound with PEO, which is consistent with the aforementioned results. In the liquid system, the energy of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of TFSI − and DFOB − was calculated (Fig.…”

Across Interfacial Li+ Conduction Accelerated by a Single-Ion Conducting Polymer in Ceramic-Rich Composite Electrolytes for Solid-State Batteries

“…The ionic conductivity of the CRCE membrane is characterized by electrochemical impedance spectroscopy (EIS) via a block cell SS/CRCE/SS from 25 to 100 °C, as shown in Figure a,b. At 25 °C, the CRCE membrane shows a high ionic conductivity of 6.60 × 10 –4 S cm –1 , and reaches 1.44 × 10 –3 S cm –1 at 60 °C, which surpasses or is comparable to the latest published results, as shown in Figure c. − Moreover, the conductivity–temperature relationship of the CRCE membrane fits in the Arrhenius equation as in eq , exhibiting a low activation energy of 0.17 eV, which demonstrates an ion-hopping mechanism in the CRCE membrane . The strong interaction induced by polyanion in the LiPVFM polymer with LATP weakens the coordination between Li + ions and polyanions and facilitates the Li + ionic conduction in the electrolyte. normalln nobreak0em0.25em⁡ σ = normalln nobreak0em0.25em⁡ italicA − italicE a / RT …”

“…(b) Arrhenius fitting of the ionic conductivity of the CRCE membrane. (c) Comparison of the ambient ionic conductivity of different composite electrolytes in references − . (d) Potentiostatic polarization curve of the CRCE membrane and EIS spectra before and after polarization.…”

The Versatile Establishment of Charge Storage in Polymer Solid Electrolyte with Enhanced Charge Transfer for LiF‐Rich SEI Generation in Lithium Metal Batteries

“…The observed increase in the electrochemical window could be attributed to electrostatic interactions occurring between porphyrins and TFSI À , resulting in the hindrance of direct oxidation reaction of CSEs. [24] Compared to the pure PEO-LiTFSI electrolyte, the electrochemical windows of the modified solid-state electrolytes are all significantly enhanced, thus showing promise for matching with high-voltage cathodes to improve battery energy density.…”