Abstract: The effect of LiNO3 as additive on electrochemical properties of lithium-sulfur batteries was investigated by charge-discharge and electrochemical impedance spectroscopy(EIS). The effect of LiNO3 on lithium anode was investigated by scanning electron microscope(SEM) and the interacting mechanisms of LiNO3 was discussed. It was found that LiNO3 adopted as additive of electrolyte formed protective surface film on lithium electrode. The film resulted in passivation at the surface of the electrode and prevented the parasitic reaction between higher-order polysulfide and lithium electrode. Cycle life and capacity of lithium-sulfur batteries were improved because the film prevented the formation of irreversible Li2S on lithium electrode. The initial discharge capacity of lithium sulfurbatteries with LiNO3 is 1172 mA·h/g. A reversible capacity of 629 mA·h/g  after 100 cycles was obtained.

Key words: LiNO3, Additive, Lithium anode, Interface film, Lithium-sulfur battery