Dual Functionalities of Carbon Nanotube Films for Dendrite-Free and High Energy–High Power Lithium–Sulfur Batteries

As a promising Li-metal battery, Li–S battery has an ultrahigh theoretical energy density of 2600 Wh kg–1. However, most of the previous work has mainly focused on tackling the “polysulfide shuttle” originating from the S cathode, while the dendrite problem coming from the Li-metal anode has often been overlooked. Herein, to solve the issues arising from both the cathode and anode simultaneously, we propose a novel cell configuration for the first time by inserting CNT films on both sides of the separator in Li–S batteries, in which the cathode-side CNT film works as a shield to suppress the “polysulfide shuttle” and the anode-side CNT film acts as a powerful shield to prevent the Li dendrite growth. In the new cell configuration, the S/rGO cathode with a high S loading of about 4.0 mg cm–2 displays a high specific capacity (1336 mAh g–1 at 0.2 C), excellent rate ability (1070, 833, 656, and 444 mAh g–1 at 0.5, 1, 2, and 5 C, respectively), and sustainable cycling stability for 150 cycles with high Coulombic efficiency (>99%) at 1 C, while the Li metal anode displays an ultrasmooth surface. We believe this work will aid in developing other metal-based (e.g., Na, K, Zn, and Al) batteries.