Realizing Scalable Nano-SiO2-Aerogel-Reinforced Composite Polymer Electrolytes with High Ionic Conductivity via Rheology-Tuning UV Polymerization

Abstract

Polymer electrolytes for lithium metal batteries have aroused widespread interest because of their flexibility and excellent processability. However, the low ambient ionic conductivity and conventional fabrication process hinder their large-scale application. Herein, a novel polyethylene-oxide-based composite polymer electrolyte is designed and fabricated by introducing nano-SiO2 aerogel as an inorganic filler. The Lewis acid–base interaction between SiO2 and anions from Li salts facilitates the dissociation of Li+. Moreover, the SiO2 interacts with ether oxygen (EO) groups, which weakens the interaction between Li+ and EO groups. This synergistic effect produces more free Li+ in the electrolyte. Additionally, the facile rheology-tuning UV polymerization method achieves continuous coating and has potential for scalable fabrication. The composite polymer electrolyte exhibits high ambient ionic conductivity (0.68 mS cm−1) and mechanical properties (e.g., the elastic modulus of 150 MPa). Stable lithium plating/stripping for 1400 h in Li//Li symmetrical cells at 0.1 mA cm−2 is achieved. Furthermore, LiFePO4//Li full cells deliver superior discharge capacity (153 mAh g−1 at 0.5 C) and cycling stability (with a retention rate of 92.3% at 0.5 C after 250 cycles) at ambient temperature. This work provides a promising strategy for polymer-based lithium metal batteries.

An Industrial Perspective and Intellectual Property Landscape on Solid-State Battery Technology with a Focus on Solid-State Electrolyte Chemistries

“…Its partnership with A123 is particularly worth noting, as the company is now testing Ionic Materials's first-generation polymer in a standard production environment for 10 Ah cells with graphite anodes and NMC 811 cathodes [69]. Recently, Ionic Materials filed a patent on solid electrolytes based on charge-transfer complexes polymer (CTCP) [70]. The CTCP improves the ionic conductivity of the polymer electrolyte by promoting lithium salt dissociation.…”

Solid-state composite electrolytes: turning the natural moat into a thoroughfare

“…The 5% SiO 2 content sample holds the highest mechanical strength to resist Li dendrite growth and the Li//Li symmetric cell demonstrates a stable cycling performance for 1400 h at 0.1 mA cm −2 and 0.1 mA h cm −2 . 72 Yu et al used SiO 2 nanoparticles as fillers but modified the SiO 2 nanoparticles’ surface with a hyper-cross-linked network of polymethyl methacrylate- co -polystyrene (PMMA- co -Ps) to enhance the compatibility with the PEO matrix. The composite SiO 2 nanoparticles with hyper-cross-linked networks were constructed by emulsion polymerization of chain segments of methyl methacrylate (MMA) and styrene (St), followed by a Friedel–Crafts alkylation reaction.…”