Few-layer MoS2 wrapped MnCO3 on graphite paper: a hydrothermally grown hybrid negative electrode for electrochemical energy storage

Abstract

This article puts forward a novel approach of combining the battery-type charge storage material, Mn(OH)2, indirectly with the two-dimensional material, MoS2, to develop the composite MnCO3@MoS2 (designated as MCMS). A single-step facile hydrothermal method is described here for the synthesis of MCMS on a low-cost graphite substrate. Furthermore, this as-synthesized binder-free electrode is utilized as the negative electrode of an all-solid state asymmetric alkaline supercapacitor, employing NiCo2O4 as the high specific energy positive electrode material. The overall asymmetric cell is shown to achieve a high specific energy of 48.97 W.h.kg−1 at 600 W.kg−1 and a high specific power of 12 kW.kg−1 at 11.33 W.h.kg−1, within a potential window of 1.2 V. Also, the composite electrode notably retains 86.5% of its gravimetric discharge capacity after 10,000 cycles with complete retention of its coulombic efficiency. The present work contributes to the development of a facile strategy for the preparation of non-carbonaceous hybrid materials suitable for high specific energy negative electrodes.