NiCo2S4 Nanocrystals on Nitrogen-Doped Carbon Nanotubes as High-Performance Anode for Lithium-Ion Batteries

Haisheng Han,Zhumabay Bakenov,Gulnur Kalimuldina,Yanli Song,Yongguang Zhang

doi:10.1186/s11671-021-03562-7

Abstract

In recent years, the development of lithium-ion batteries (LIBs) with high energy density has become one of the important research directions to fulfill the needs of electric vehicles and smart grid technologies. Nowadays, traditional LIBs have reached their limits in terms of capacity, cycle life, and stability, necessitating their further improvement and development of alternative materials with remarkably enhanced properties. A nitrogen-containing carbon nanotube (N-CNT) host for bimetallic sulfide (NiCo2S4) is proposed in this study as an anode with attractive electrochemical performance for LIBs. The prepared NiCo2S4/N-CNT nanocomposite exhibited improved cycling stability, rate performance, and an excellent reversible capacity of 623.0 mAh g–1 after 100 cycles at 0.1 A g–1 and maintained a high capacity and cycling stability at 0.5 A g–1. The excellent electrochemical performance of the composite can be attributed to the unique porous structure, which can effectively enhance the diffusivity of Li ions while mitigating the volume expansion during the charge–discharge processes.

Highlights

Lithium-ion battery (LIB) is a leading battery technology used in portable electronic devices, electric vehicles, and renewable energy storage [1, 2]
The N atoms were doped into the carbon nanotubes (CNT) via a hydrothermal reaction at 170 °C, while Binary nickel– cobalt sulfide (NiCo2S4) was grown in situ on the surface of CNTs
The crystal structures of NiCo2S4, NiCo2S4/CNT, and NiCo2S4/nitrogen-containing carbon nanotube (N-CNT) composites were characterized by X-ray powder diffraction (XRD) (Fig. 1a)

Summary

Introduction

Lithium-ion battery (LIB) is a leading battery technology used in portable electronic devices, electric vehicles, and renewable energy storage [1, 2]. The specific energy density of a commercial graphite anode material reached its theoretical capacity of 372 mAh g–1, which does not leave much room for its further enhancement to satisfy the performance requirements of emerging electronics and electric vehicle technologies [6, 7]. Transition-metal sulfides (TMSs) offer remarkably higher specific capacity than traditional electrode materials [8–12]. TMSs have been reported as anodes with excellent conductivity and catalytic activity. Binary nickel–cobalt sulfide (NiCo2S4) exhibits a high theoretical specific capacity (703 mAh g–1), an excellent electronic conductivity (1.26 × 106 S m–1), and a greater abundance of redox reaction sites [13–17]. The reported general charge/discharge mechanism of NiCo2S4 with lithium (Li) involves the following reactions: NiCo2S4 + 8Li+ + 8e− → Ni + Co + 4Li2S (1)

Methods

Results

Conclusion