Ga/Ta co-doped LLZO enhanced voltage tolerance and lithium dendrite resistance of composite solid electrolytes

The all-solid-state lithium batteries (ASSLBs) are widely acknowledged as the most promising candidate for energy storage devices due to their excellent safety features and high energy density. However, ASSLBs face significant challenges in terms of low ionic conductivity and the formation of lithium dendrites. Excitingly, composite solid-state electrolytes offer promising solutions to critical challenges. Here, we report a PEO-LiTFSI/LGLZTO organic-inorganic composite solid-state electrolytes (O-ICSEs). A high-performance Li6.4Ga0.10La3Zr11.7Ta0.30O12 particles, co-doped with Ga and Ta, was incorporated into matrices of poly (ethylene oxide) (PEO) and lithium bis(trifluoro-methylsulfonyl)imide (LiTFSI) to establish a continuous pathway for the transportation of Li+. Additionally, the synergistic effect of Ga and Ta enhances the Li+ transport capability within the LGLZTO particles. PEO-LiTFSI/LGLZTO O-ICSEs, which have fast ion transport channels, exhibit exceptional ionic conductivity (4.35 × 10−4 S cm−1 at 60 °C) and possess a wide and stable electro- chemical window (5.5 V). The Li||PL(Ga0.10Ta0.30)25||Li cell demonstrates an outstanding cycle life exceeding 1000 h at a current density of 0.2 mAh cm−2. The prominent electrochemical performance of PL(Ga0.10Ta0.30)25 O-ICSEs can primarily be attributed to their excellent electrode/electrolyte interfacial compatibility and effective suppression of Li dendrite growth. The proposed PL(Ga0.10Ta0.30)25 O-ICSEs offer a promising solution for designing highly efficient ASSLBs.