Dendrite-Free Solid-State Li Metal Batteries Enabled by Bifunctional Polymer Gel Electrolytes

Gel electrolytes have attracted great attention due to the high ionic conductivity and superior mechanical strength. However, poor interfacial stability between Li metal and gel electrolytes hinders their practical application. Here, a double polymer network gel electrolyte (DPNGE) is prepared via photopolymerizing branched acrylate on the poly(vinylidene fluoride-co-hexafluoropropylene) matrix to solve this issue. This DPNGE possesses an enhanced ionic conductivity of 9.5 × 10–4 S cm–1 at room temperature and a wide electrochemical stability window up to 5.0 V. The assembled Li/DPNGE/LiFePO4 batteries demonstrated a 153.7 mA h g–1 initial discharge capacity at 0.5 C and keep 92.7% capacity retention after more than 500 cycles. Moreover, a systematic analysis confirms that we construct a stable solid electrolyte interphase layer for homogeneous deposition and a stable cycle. These advantages enable the prepared DPNGE to show great application potential in high-performance lithium metal batteries.