Locally boosted Li2S nucleation on VO2 by loading carbon quantum dots for soft-packaged lithium–sulfur pouch cells

Abstract

VO₂ affords ultrafast polysulfide adsorption on account of its oxidation potential, which matches the sulfur working window (1.7–2.8 V). Nevertheless, its nonconductive surface limits direct sulfur conversion. Herein, we gently load carbon quantum dots on VO₂ to increase direct Li₂S nucleation by enhanced electron conductivity. As a result, the soft-packaged lithium–sulfur pouch cell yields a capacity retention of 88.8% at 0.5C after 100 cycles and a decay rate of 0.17% per cycle over 200 cycles at 2C. The cell energy density of the multilayer cell is up to 386.1 W h kg⁻¹.