An interactive organic-inorganic composite interface enables fast ion-transport, low self-discharge and stable...

Lithium batteries have been widely used in various fields, however, further research needs to be conducted to improve their stability and long-term storage performance for the highly active lithium metal anode. Herein, an organic-inorganic composite film composed of polypropylene carbonate (PPC), lithium bis(trifluoromethanesulphonyl)imide (LiTFSI) and Li_6.5La₃Zr_1.5Nb_0.5O₁₂ (LLZNO) is fabricated on the lithium foil surface by spin-coating technique to passivate the lithium anode and regulate the ion transport behavior. The Li/CF_x battery with the optimized composite film coated lithium anode exhibits excellent discharge capacity (1006.6 mAh/g, 0.1C) and high-rate capability (639.4 mAh/g, 5C), much higher than those of the uncoated Li/CF_x battery. The discharge specific capacity remains 521.7 mAh/g at 0.1C after stored at 55 °C for 60 days, corresponding to a monthly self-discharge of 1.87 %, while the battery without coating film has almost failed. Theoretical calculation, Raman mapping and Kelvin probe force microscopy (KPFM) measurements demonstrate that the stable and ion-conductive composite film effectively increases ion channels, regulates ion migration and passivates the Li anode from the corrosion of liquid electrolyte during discharge and storage. Constructing a rational organic-inorganic composite film with high mechanical stability and ionic conductivity on the Li anode surface is a facile and cost-effective strategy to enhance the high-rate and long-term storage performance of Li/CF_x battery.