Hybrid Dynamic Covalent Network as a Protective Layer and Solid-State Electrolyte for Stable Lithium-Metal Batteries

Abstract

Lithium (Li) metal is a highly promising anode material for next-generation high-energy-density batteries, while Li dendrite growth and the unstable solid electrolyte interphase layer inhibit its commercialization. Herein, a chemically grafted hybrid dynamic network (CHDN) is rationally designed and synthesized by the 4,4′thiobisbenzenamine cross-linked poly(poly(ethylene glycol) methyl ether methacrylate-r-glycidyl methacrylate) and (3-glycidyloxypropyl) trimethoxysilane-functionalized SiO 2 nanoparticles, which is utilized as a protective layer and hybrid solid-state electrolyte (HSE) for stable Limetal batteries. The presence of a dynamic exchangeable disulfide affords self-heability and recyclability, and the chemical attachment between SiO 2 nanoparticles and the polymer matrix enables the homogeneous distribution of inorganic fillers and mechanical robustness. With integrated flexibility, fast segmental dynamics, and autonomous adaptability, the as-prepared CHDN-based protective layer enables superior electrochemical performance in half cells and full cells (capacity retention of 83.7% over 400 cycles for the CHDN@Li/LiFePO 4 cell at 1 C). Furthermore, benefiting from intimate electrode/electrolyte interfacial contact, CHDN-based solid-state cells deliver excellent electrochemical performance (capacity retention of 89.5% over 500 cycles for the Li/HSE/LiFePO 4 cell at 0.5 C). In addition, the Li/HSE/LiFePO 4 pouch cell exhibits superior safety, even exposing various physical damage conditions. This work thereby provides a fresh insight into a rational design principle for dynamic network-based protective layers and solid-state electrolytes for battery applications.

Tailoring the interface of lithium metal batteries with an in situ formed gel polymer electrolyte

“…The Li 2 CO 3 , an intrinsic component of the SEI film, is originated from the decomposition of the ester solvents. 46 Combining the C 1s spectra (Fig. S8b†) with Li 1s spectra (Fig.…”

“…49 The lower content of Li x PF y in the Li|c-PH 6 C 9 -GPE|Li battery suggests that the c-PH 6 C 9 polymer matrix could inhibit the decomposition of LiPF 6 in LE. 46 Therefore, it is supposed that c-PH 6 C 9 -GPE can modify the composition of the SEI film, facilitate rapid transference of Li + , homogenize the Li + flux and promote a more uniform Li deposition.…”

Control of Lithium Salt Partitioning, Coordination, and Solvation in Vitrimer Electrolytes

“…Solid-state electrolytes have been investigated extensively as potentially safer alternatives to flammable and toxic liquid electrolytes − and exhibit good interfacial contact with electrodes. − Poly­(ethylene oxide) (PEO) is a common chemical motif known to facilitate lithium ion transport by ion coordination with the backbone ether oxygens. − Although PEO-based polymer electrolytes show high ionic conductivity, , these materials exhibit relatively low conductivity at room temperature and a strong temperature-dependent modulus that drops substantially upon heating. − To enhance their mechanical properties, PEO can be covalently or noncovalently cross-linked, leading to rubbery electrolytes (characteristic plateau modulus ∼0.1 MPa) with suppressed dendrite formation due to the nanoscale mesh size in cross-linked PEO. ,, However, covalent permanent networks are not easily reprocessed or recycled after the curing processes. In recent years, vitrimers have received increased attention as robust and recyclable solid polymer electrolytes. − Various dynamic bonds such as boronic ester, ,,, imine, − ,, vinylogous urethane, boroxine, and disulfide ,,− have been previously incorporated into vitrimers for solid-state electrolyte applications. Soy protein-based imine (SPI) dynamic networks were prepared by the Fang group .…”