Elucidating the Intercalation Pseudocapacitance Mechanism of MoS₂–Carbon Monolayer Interoverlapped Superstructure: Toward High-Performance Sodium-Ion-Based Hybrid Supercapacitor

Abstract

Two-dimensional (2D) layered materials have shown great promise for electrochemical energy storage applications. However, they are usually limited by the sluggish kinetics and poor cycling stability. Interface modification on 2D layered materials provides an effective way for increasing the active sites, improving the electronic conductivity, and enhancing the structure stability so that it can potentially solve the major issues on fabricating energy storage devices with high performance. Herein, we synthesize a novel MoS-carbon (MoS-C) monolayer interoverlapped superstructure via a facile interface-modification route. This interlayer overlapped structure is demonstrated to have a wide sodium-ion intercalation/deintercalation voltage range of 0.4-3.0 V and the typical pseudocapacitive characteristics in fast kinetics, high reversibility, and robust structural stability, thus displaying a large reversible capacity, a high rate capability, and an improved cyclability. A full cell of sodium-ion hybrid supercapacitor based on this MoS-C hybrid architecture can operate up to 3.8 V and deliver a high energy density of 111.4 Wh kg and a high power density exceeding 12 000 W kg. Furthermore, a long cycle life of 10 000 cycles with over 77.3% of capacitance retention can be achieved.

2D Nanospace Confined Synthesis of Pseudocapacitance‐Dominated MoS2‐in‐Ti3C2 Superstructure for Ultrafast and Stable Li/Na‐Ion Batteries

“…Their nature 2D nanostructure with atomic layer thickness gives rise to many extraordinary physicochemical properties, e.g., large interlayer spacing, high active surface, and abundant edges. These features can contribute extremely high pseudocapacitance and rapid reaction kinetics . For instance, the most representative MoS 2 among them usually delivers a high measured specific capacity (>800 mAh g −1 ) beyond the theoretical value (670 mAh g −1 ) for both LIBs and SIBs .…”

Enhanced Ionic/Electronic Transport in Nano‐TiO2/Sheared CNT Composite Electrode for Na+ Insertion‐based Hybrid Ion‐Capacitors

“…Supercapacitors, on the other hand, store charge via a physical adsorption and desorption of charged species on the surface of the electrode and which is not kinetically limited. However, the amount of charge stored is smaller than that of batteries, resulting in high power densities but low energy densities (only 2–5 Wh kg −1 ) . Recently, a class of materials has been shown to demonstrate so‐called “ion‐insertion‐based pseudo‐capacitance”, meaning that they do not exhibit diffusion limitations for ion insertion.…”

Advanced Materials for Sodium‐Ion Capacitors with Superior Energy–Power Properties: Progress and Perspectives

“…Moreover, MoS 2 nanosheet architecture can facilitate the migration of Na + due to the short diffusion pathways. Zhang and co‐workers reported a novel MoS 2 –carbon nanocomposite with monolayer interoverlapped architecture via a facile interlayer‐modification route. The architecture is highly beneficial to realize high rate and long cycle life.…”