The Optimization of a Carbon Paper/MnO₂ Composite Current Collector for Manufacturing a High-Performance Li–S Battery Cathode

Abstract

High theoretical energy density endows lithium–sulfur batteries to be a promising candidate of the secondary batteries. Numerous studies have been implemented relying on exploring efficient host materials or separator modifying layers to solve the problematic shuttling and insufficient conversion of soluble polysulfides, whereas few studies have focused on the modification of the cathode collector. Herein, a high-performance sulfur cathode is manufactured with carbon paper/MnO2 as the cathode collector and liquid lithium polysulfides as the electrode material. The interface of carbon paper/MnO2 is proposed to afford fast electronic transport, strong chemical adsorption, and effective electrocatalysis to confine the diffusion of lithium polysulfides and facilitate their conversion during the charge/discharge process. More importantly, with no conductive additives and binders assisting, the gravimetric energy density of the sulfur cathode could be largely improved. Specifically, lithium–sulfur batteries using carbon paper/MnO2 as a cathode collector could stably circulate for 200 cycles at 0.2 C with a capacity of 664 mAh g−1, which is higher than that of carbon paper as a cathode collector (486 mAh g−1). This work may provide a new perspective to enhance the electrochemical performance of lithium–sulfur batteries by optimizing the cathode collector.

Keywords

• Li–S battery
• carbon paper
• MnO₂
• hybrid collector
• optimization