An Ion‐Dipole‐Reinforced Polyether Electrolyte with Ion‐Solvation Cages Enabling High–Voltage‐Tolerant and Ion‐Conductive Solid‐State Lithium Metal Batteries

Abstract

Solid‐state electrolytes (SSEs) with sufficient ionic conduction, wide voltage window, flexible‐rigid interface, and ease of processibility are determinative to the development of energy‐dense solid‐state lithium metal batteries. Due to the low density and interfacial compatibility, polyether SSE has been studied for decades but remains handicapped by the inherently low ionic conductivity and insufficient voltage window. In this contribution, an ion‐dipole‐reinforced poly‐3‐hydroxymethyl‐3‐methyloxetane is demonstrated as a novel SSE and major substitution to conventional poly(ethylene oxide). By further polypropylene skeleton compositing, the composite solid electrolyte (PHMP) synergistically achieves high voltage tolerance (4.6 V), high ion‐conduction (25 °C, 1.26 × 10−4 S cm−1), and flexible‐rigid mechanical properties. Cryo‐transmission electron microscope has revealed a columnar Li deposition and LiF‐rich solid electrolyte interface, suggesting excellent dendrite suppression. According to density functional theory, the densely branched ether–oxygen groups play an important role as ion solvation cages, favoring strong Li+‐coordination and fast diffusion kinetics. More importantly, it restrains the proton‐induced decomposition and essentially enhances high‐voltage stability. As a result, PHMP contributes to an improved rate capability, significantly reduced interface impedance, and long‐term cycle stability of Li symmetrical batteries for over 1600 h. PHMP‐modified LiNi0.8Co0.1Mn0.1O2|Li batteries exhibit a high discharge capacity of 211.5 mAh g−1 and desirable cycle stability.

In situconstruction of polyether-based composite electrolyte with bi-phase ion conductivity and stable electrolyte/electrode interphase for solid-state lithium metal batteries

“…Meanwhile, the PDOL phase permeated in LLTO can achieve rapid ion conduction through the coupling/decoupling of O and Li + in the -CH 2 -CH 2 -O-CH 2 -Opolymer chains. 13,28 To further analyze the topochemistry of PDOL, nuclear magnetic resonance (NMR) measurements were performed (Fig. 1e).…”

“…2e and S6 †), which signicantly exceeds that of the traditional PEO electrolyte (t Li + ¼ 0.2). 13,31 This can be attributed to the fact that the continuous functional -C-Ogroups in the PDOL network can provide unique ion coordination for Li + and accelerate ion migration. Considering that the conductivity of SPE is in connection with its amorphous state and the free volume from rubber to viscoelastic state above the glass transition temperature (T g ), differential scanning calorimeter (DSC) tests were carried out to study the thermal behavior of PDOL.…”

“…[9][10][11] However, the traditional polyethylene oxide (PEO) electrolyte, one of the main commercial electrolytes, faces many obstacles, including insufficient ionic conduction (10 À6 to 10 À8 S cm À1 , at room temperature) and a low oxidation potential (3.8 V vs. Li/Li + ). [12][13][14] Composite polymer electrolytes (CPEs) can bridge the above gaps by integrating active inorganic llers into polyether electrolytes. [15][16][17] The rigid inorganic llers in CPEs, with their inherent high ion conductivity, play a critical role in suppressing the agglomeration of polymer chains and accelerating the dissociation of Li salt.…”

An Unprecedented Fireproof, Anion‐Immobilized Composite Electrolyte Obtained via Solidifying Carbonate Electrolyte for Safe and High‐Power Solid‐State Lithium‐Ion Batteries

“…Thanks to the strong lithium bond and Coulomb force, the binding energy of the LTC-[PF 6 − ] pair is much higher than that of previously reported ionmolecular pair (generally −5 eV). [20] The polyfunctionality of LTCs also enables them to form polydentate coordination with anions (Figure 3a), which is possible to establish a dynamic network and provides a more powerful constraint to hinder anion transport. Furthermore, this network may contribute to the solidification of the electrolyte.…”

Percolated Sulfide in Salt‐Concentrated Polymer Matrices Extricating High‐Voltage All‐Solid‐State Lithium‐metal Batteries

“…[15][16][17][18] Nevertheless, the bottlenecks of polymer electrolytes, including insufficient 𝜎 Li + and limited oxidation stability, hindering their further commercialization in future lithium batteries applications. [19][20][21][22] This issue is even more pronounced in the pursuit of high energy density systems while employing high voltage cathodes. [19] To resolve the problem of low 𝜎 Li + owing to the comparatively slow motion of polymer side chains, [23] researchers embed inorganic fillers into the polymer matrix to adjust the ionic transportability.…”