Conversion from Li2SO4 to Li2S@C on carbon paper matrix: A novel integrated cathode for lithium-sulfur batteries

Integral construction of lithium sulfide (Li2S) cathode is indispensable and vital for developing high-performance lithium-sulfur (Li-S) batteries. Herein we have demonstrated a facile strategy for fabricating free-standing carbon paper supported Li2S@C (P-Li2S@C) integrated cathode. The P-Li2S@C cathode is synthesized through simple pyrolysis of low-cost lithium sulfate (Li2SO4) and chitosan, and embedded in the double carbon matrixes with carbon paper support and outer CVD-carbon layer. Li2S nanoparticles are homogeneously dispersed in the above designed double carbon matrixes. The P-Li2S@C cathode exhibits an initial discharge capacity of 820 mAh g−1 at 0.1 C and still maintains 430 mAh g−1after 100 cycles, superior to the P-Li2S counterpart (480 mAh g−1 at 0.1 C and 150 mAh g−1 after 100 cycles). Our research verifies the effectiveness of double carbon modification on the Li2S, especially, the outer carbon coating not only improves the electrical conductivity of electrode, but also further prohibits the “shuttle effect” of polysulfides.