Refining Interfaces between Electrolyte and Both Electrodes with Carbon Nanotube Paper for High-Loading Lithium-Sulfur Batteries.

Lithium sulfur (Li-S) batteries are appealing energy storage technologies because of their high theoretical energy density and low cost. However, Li-S batteries suffer from poor practical energy density due to serious polysulfide dissolution and shuttle, as well as lithium anode corrosion. Herein, we provide a dual-protection strategy for the high-energy-density Li-S cell by inserting two nanotube paper (CNTp) interlayers on both electrodes. The CNTp interlayers can provide stable interfaces for both the cathode and anode, facilitating the formation of uniform charge transfer and ion flue. As a result, the Li-S cell exhibits stable cycling performance and great rate ability up to a high rate of 5 C (5 C = 25 mA cm). Even at an ultrahigh sulfur load of 12.1 mg cm, a high areal capacity of 12.6 mAh cm is still achieved, which can remain at 11.1 mAh cm after 30 cycles (corresponding to 917 mAh g). The refined interfaces between the electrolyte and both electrodes are further confirmed by the micro-zone current distribution and COMSOL simulation. Our approach provides an effective and universal strategy to improve the electrochemical stability of the Li-S cell at high sulfur load, opening a new platform for designing advanced metal cell systems.