Integration of nickel phosphide nanodot-enriched 3D graphene-like carbon with carbon fibers as self-supported sulfur hosts for advanced lithium sulfur batteries

Abstract

Lithium-sulfur batteries are spotlighted as the promising next-generation batteries because of their high energy density and low-cost. Nevertheless, intrinsic low conductivity, notorious shuttle effect, and sluggish redox kinetics of sulfur cathode greatly impede their commercialization. Herein, we design and demonstrate a powerful combined strategy to build a novel hybrid architecture for hosting sulfur, which are achieved by growing Ni P nanodot-enriched 3D graphene-like carbon onto carbon fiber paper (NP-3DGC@CFP) via a facile one-step carbonization approach. In the integrated NP-3DGC@CFP/S electrode: micro-mesoporous 3DGC provides abundant space and complicated pore structures to accommodate sulfur and physically confine polysulfide species; polar Ni P nanodots chemically immobilize the lithium polysulfides and accelerate electrochemical reaction kinetics; flexible CFP serves as mechanical scaffold to support the electrode and avoids binder-related limitations. As a result, self-supported NP-3DGC@CFP/S cathode demonstrates an excellent combination of capacity, rate, cycling endurance (1409.4 mAh g at 0.1 C, 538.2 mAh g at 5 C, 786.3 mAh g with 72.7% retention at 0.5 C for 300 cycles) and anti-self-discharge capability. Significantly, such cathode also shows satisfied cycling stability at a high sulfur loading of 6.5 mg cm or at a high rate of 2 C, demonstrating its bright perspective for practical application.