The design of nanostructured sulfur cathodes using layer by layer assembly

Abstract

Sulfur as a conversion cathode has a high theoretical capacity of 1672 mA h g⁻¹ and a theoretical energy density of 3600 W h kg⁻¹ in the Li–S battery. The theoretical energy density is five times larger than that of a conventional lithium ion battery. Various challenges have hindered the use of this highly attractive cathode including the insulating nature of sulfur and poor electrode stability resulting in an irreversible capacity loss due to polysulfide migration from the cathode to the anode. Here we show a simple, scalable, room temperature bottom up approach for the synthesis of a nanostructured sulfur cathode which comprises a sulfur particle embedded with hollow carbon nanospheres encapsulated with polyelectrolyte multilayers. We demonstrate that specific capacity, rate capacity and cycling stability of the Li–S battery are significantly affected by the selection of polyelectrolyte multilayers.