Synthesis of free-standing CoxP/Co3(PO4)2/C composite nanofiber mats and their characteristics as multi-functional interlayers for lithium–sulfur batteries
Ayaulym Belgibayeva, Makpal Rakhatkyzy, Adi Akylbek, Izumi Taniguchi
Chem Electro Chem
The free-standing c obalt phosphides-based composite nanofiber mats with different compositions (Co y P/C, Co x P/Co 3 (PO 4 ) 2 /C, where 2>x>y>1) were synthesized by electrospinning with heat treatments and applied as multi-functional interlayers for lithium–sulfur batteries. The polisulfide confining ability of the interlayers was evaluated by a static polysulfide adsorption test and an electrochemical conversion test using symmetric cells. The Co x P/Co 3 (PO 4 ) 2 /C exhibits better catalytic performance for converting polysulfides, owing to the combination of Co x P catalyst with a strong polysulfide chemisorbers Co 3 (PO 4 ) 2 and P-doped carbon. As a result, the lithium–sulfur cell with this interlayer delivered a high initial discharge capacity of 1483 mAh g –1 at 0.1 C, retaining 705 mAh g –1 after 200 cycles at 0.5 C with 100% Coulombic efficiency. The polysulfide trapping by the interlayer was further elucidated from the results of its ex situ characterizations after discharge and charge processes at different cycles in lithium–sulfur cells.
nanofiber, catalyst, lithium-sulfur cells