2D Nanochannel Interlayer Realizing High-Performance Lithium-Sulfur Batteries.

Commercialization of lithium-sulfur (Li-S) batteries is largely limited by polysulfide shuttling and sluggish kinetics. Herein, 2D nanochannel interlayer composed of alternatively-stacked porous silica nanosheets (PSN) and TiCT-MXene are developed. The 2D nanochannels with selective cation transport characteristics facilitate lithium ion rapid transport, while reject the translocation of polysulfide anions across the separator. The hydroxylated MXene shifts the p-band center of the surface O on PSN closer to the Fermi level, leading to strong absorptive/catalytic effect for polysulfides and thus fast polysulfide transformation kinetics. Together with the ion/electron bi-conduction function of PSN/MXene, the Li-S batteries deliver high initial capacity of 1443 mAh g at 0.1 C, low-capacity decay rate of 0.049% per cycle over 800 cycles at 2 C, and excellent rate capability. At a high sulfur loading of 5.2 mg cm, the cells present higher areal specific capacity than commercial lithium ion batteries. The pouch cells with lean electrolyte (E/S = 3.9 µL mg) yield a capacity of 2-Ah at 100 mA, high energy density and excellent cycling stability. This contribution opens up new avenues for expanding application of 2D nanofluidics in electrochemical energy storage and conversion.