Wire-Shaped Li-Ion Battery Based on Iron Sulfide Nanostructures on Carbon Based Electrode

Abstract

In recent years, the development of new materials, electrode architectures and manufacturing strategies has opened Li-ion batteries to new application areas. In particular, the implementation of high-performances and reliable energy storage devices is a challenging task in the sector of smart-fabrics and wearable electronics. Wire-shaped batteries (WSBs) are one of the most active and rapidly growing research fields, because of their flexibility and easy integration in fabrics. The development of a suitable technique for the production of graphene fibers as electrodes boosted the interest in WSBs [1]. Typically, Li-ion WSBs rely on self-supported all-carbon electrodes made of reduced graphene oxide (RGO) and/or carbon nanotubes (CNTs) fibers [2], synthesized through the wet-spinning process. The incorporation of higher capacity active materials in carbon fibers like TiO2 nanosheets [3], SiO2 [4] and S nanoparticles [5,6] has already been demonstrated as a successful strategy to further increase battery performances. However, the incorporation of active material during the wet-spinning of the carbon-based fibers limits this technique to 2D materials only. Here, we propose Li-ion WSB based on RGO fibers electrode and iron sulfide. Iron nanostructures have been deposited on RGO fibers by an easy electrochemical route and converted in iron sulfide as active material through sulfurization process by thermal treatment in presence of sulfur. Half-cell configuration with Li wire as cathode has been evaluated as well as a full-cell configuration. Electrochemical stability of the active materials were investigated through cyclic voltammetries while capacity, efficiency and cycle stability were evaluated for both half-cell and full-cell configurations. Morphological and structural investigations were performed on the electrodes by means of SEM, XRD and Raman analysis.