Effects of Nickel Particle Size and Graphene Support on the Electrochemical Performance of Lithium/Dissolved Polysulfide Batteries

Highlights: • Electrodes with different nano size Ni particles are prepared. • The electrocatalytic effect of Ni nanoparticle sizes is investigated. • The graphene supported Ni nanoparticle is synthesized. • The effect of the graphene support to the anchor Ni nanoparticle is investigated. • Ni/graphene electrode exhibits remarkably enhanced discharge capacity. - Abstract: The electrocatalytic effect of nickel (Ni) nanoparticle sizes on the lithium polysulfide conversion reactions in dissolved lithium sulfur battery configuration is investigated. The Ni particles of 20 nm with the higher cathode surface area show a superior capacity of 1066 mAh g⁻¹ sulfur compared to Ni particles of 40 and 100 nm for the first cycle. In addition, to further improve the capacity retention and discharge capacity of the cell, the effect of the graphene support on Ni nanoparticle dispersion and cycling performance is investigated. The results show a significant improvement in the discharge capacity compared to the other electrodes. This could be explained by the homogeneous distribution of Ni nanoparticle within the carbon matrix, which suppress the agglomeration and surface area loss of the Ni nanoparticle after cycling; as well as a synergetic effect of graphene structure and Ni nanoparticle.