• Gerbaldi, Claudio
• Ruffo, Riccardo
• Mustarelli, Piercarlo
• Colombo, Francesco
• Ferrara, Chiara
• Bonizzoni, Simone
• Mauri, Michele
• Falco, Marisa
• Simonutti, Roberto

Abstract

<jats:p>Lithium Metal Batteries (LMB) require solid or quasi-solid electrolytes able to block dendrites formation during cell cycling. Polymer-in-ceramic nanocomposites with the ceramic fraction exceeding the one normally used as the filler (&gt;10 ÷ 15 wt%) are among the most interesting options on the table. Here, we report on a new hybrid material encompassing brush-like TiO<jats:sub>2</jats:sub> nanocrystals functionalized with low molecular weight poly(ethylene oxide) (PEO). The nanocomposite electrolyte membranes are then obtained by blending the brush-like nanocrystals with high molecular weight PEO and LiTFSI. The intrinsic chemical compatibility among the PEO moieties allows a TiO<jats:sub>2</jats:sub> content as high as ∼39 wt% (90:10 w/w functionalized nanocrystals/PEO-LiTFSI), while maintaining good processability and mechanical resistance. The 50:50 w/w nanocomposite electrolyte (18.8 wt% functionalized TiO<jats:sub>2</jats:sub>) displays ionic conductivity of 3 × 10<jats:sup>−4</jats:sup> S cm<jats:sup>−1</jats:sup> at 70 °C. Stripping/plating experiments show an excellent long-term behavior even at relatively high currents of 200 <jats:italic>μ</jats:italic>A cm<jats:sup>−2</jats:sup>. Upon testing in a lab-scale Li/electrolyte/LiFePO<jats:sub>4</jats:sub> cell, the material delivers 130 mAh g<jats:sup>−1</jats:sup> and 120 mAh g<jats:sup>−1</jats:sup> after 40 and 50 cycles at 0.05 and 0.1 mA, respectively, with Coulombic efficiency exceeding 99.5%, which demonstrates the very promising prospects of these newly developed nanocomposite solid electrolyte for future development of LMBs.</jats:p>

Topics

• nanocomposite
• polymer
• experiment
• Lithium
• ceramic
• molecular weight