Abstract
Rationally constructing an interlayer to suppress the lithium polysulfide (LiPS) shuttling but allow fast transport of Li-ions is of great significance for high-density Li–S batteries. Despite numerous nanomaterials have been explored, an effective approach to fabricate an ideal interlayer is still elusive. Herein, we developed a new electropolymerization strategy to grow in-situ a polycarbazole-type interlayer with a number of merits to boost the reversible capacity. Firstly, the membrane is microporous but compact with uniform 0.82 nm nanochannels that can effectively suppress the diffusion of polysulfide species. Secondly, using the CNT (700 nm) as conductive substrate, the electropolymerized membrane is ultrathin (60 nm), which facilitates fast transport of lithium ions and rate performance. Thirdly, the membrane is electron conductive (23 S m−1) that benefits the charge transfer and redox reaction. Li–S batteries configured with such an UCCM type of interlayer have showed enhanced sulfur utilization by threefold, with a reversible capacity of 920 mA h g−1 after 600 cycles at 0.2 C, and a high areal density of 10 mAh cm−2 at 11.2 mg cm−2 sulfur loading. A safer lithium-ion sulfur full-cell with lithiated graphite anode demonstrated a stable capacity over 4 mAh cm−2 under a low electrolyte/sulfur ratio of ~10 μL mg−1.
An ultrathin, continuous, and conductive microporous sieving membrane was grown in-situ on Li–S separator via an electropolymerization technique. This novel technique significantly inhibits the polysulfide shuttling, provides fast pathways for Li+ transport, and enhances charge transfer kinetics. [Display omitted]
•An electropolymerization approach is developed to grow high-performance interlayers for Li–S battery.•Such an interlayer is ultrathin, continuous, microporous with desired conductivity and polysulfides suppression ability.•Li–S full cell shows a reliable capacity (10 mAh cm−2) at 11.2 mg cm−2 sulfur loading.•The electropolymerization mechanism is explored as a universal nanofilms fabrication method.