Design and synthesis of an interfacial layer of the polysulfide immobilizer for lithium-sulfur batteries by the one-pot hydrothermal method

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>To overcome the low electrical conductivity and large volume expansion of a sulfur cathode during electrochemical reactions, a composite of SnO<SUB>2</SUB> nanoparticles with 5–10 nm size dispersed on reduced graphene oxide (rGO) sheets and sulfur (rGO/SnO<SUB>2</SUB>/S) was prepared by a one-pot hydrothermal process. This cathode shows 1.2-fold higher interfacial Li ion diffusivity (1.8 × 10<SUP>−12</SUP> cm<SUP>2</SUP> s<SUP>−1</SUP>) than that of an rGO/S cathode (1.5 × 10<SUP>−12</SUP> cm<SUP>2</SUP> s<SUP>−1</SUP>). This improvement is attributed to the synergistic effect of the hybrid matrix comprising rGO sheets and SnO<SUB>2</SUB>. The rGO sheets provide a fast electron pathway and accommodate a large amount of sulfur. Moreover, the dispersed SnO<SUB>2</SUB> nanoparticle acts as an immobilizer to prevent the dissolution of polysulfide during the electrochemical reaction. The synthesized rGO/SnO<SUB>2</SUB>/S cathode also exhibits an electrical resistivity of 4.4 × 10<SUP>−1</SUP> Ω cm due to interfacial modification. Further, it exhibits improved electrochemical performance with an initial discharge capacity of 1591.57 mA h g<SUP>−1</SUP> at 0.1 C, which stabilizes to 606.98 mA h g<SUP>−1</SUP> at 0.2 C after 100 cycles. In addition, it shows a discharge capacity of 575.45 mA h g<SUP>−1</SUP> even at a high current density of 5 C.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The hybrid sulfur host is composed of reduced graphene oxide (rGO) and tin oxide (SnO<SUB>2</SUB>) nanoparticles. </LI> <LI> The rGO and SnO<SUB>2</SUB> act as a conductive accommodator and catalytic immobilizer of polysulfide, respectively. </LI> <LI> It exhibits significantly improved electrochemical performance than pristine sulfur cathode. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>