Flexible pore structure modulation enables durable sulfur carrier for advanced lithium–sulfur batteries

Abstract

A number of strategies have been proposed to deal with intrinsic sulfur problems in lithium–sulfur batteries, while the most representative and effective strategy is the utilization of porous carbon as a sulfur container. However, it should be admitted that conventional preparation routes for porous carbon are complicated and generally involve high-temperature processing, which increases the cost and production difficulty. In this work, a facile hydrothermal tactic was put forward to fabricate oxidized porous carbon materials (OPCBs) for lithium–sulfur (Li–S) batteries. The specific surface area of OPCBs and the size of the formed pores could be flexibly adjusted by regulating hydrothermal conditions, simultaneously retaining the intact structure of the particles, even without seriously affecting the conductivity of carbon/sulfur composites in some OPCBs. Polar interfaces introduced by hydrothermal processing could immobilize long-chain lithium polysulfide via the chemical interaction, whereas the appearance of micro–mesoporous structure played a critical role in physical restrictions of sulfur species and offered a more rapid lithium-ion transmission pathway during cycling. As a result, the optimized OPAB-140-1.5@S delivered a superior comprehensive cycle performance, which maintained quite an impressive reversible capacity of 602 mA h g⁻¹, even after 400 cycles with a low decay rate of 0.08% per cycle. In addition, the tailor-made pore structures with different characteristics prepared by the straightforward technique provide some enlightenment on the potential orientation to multi-field applications.