Unveiling the reaction mechanism of an Sb2S3-Co9S8/NC anode for high-performance lithium-ion batteries.

Metal sulfides are promising lithium-ion battery anode materials with high specific capacities, but there has been little in-depth discussion on the reaction mechanism of metal sulfides. In this study, a robust bimetallic sulfide heterogeneous material (Sb2S3-Co9S8/NC) based on a metal-organic framework was designed. The combination of in situ X-ray diffraction and ex situ transmission electron microscopy revealed the phase evolution behavior during the first cycle. During the lithiation process, Sb2S3 undergoes lithium insertion, conversion and alloying reactions to form crystalline Li2S, Li3Sb and metallic Sb. Co9S8 undergoes lithium insertion and transformation to form metallic Co and Li2S. Lithium ions are extracted from the nanocrystalline phase and transformed into the original Sb2S3 and Co9S8 phases. The Sb2S3-Co9S8/NC anode exhibits excellent cycle stability (616 mA h g-1 at 2 A g-1 after 900 cycles) and fast lithium ion transfer kinetics. These results demonstrate the lithiation/delithiation mechanism of the Sb2S3-based anode and provide a new path for the development of high-performance LIB anodes based on bimetallic sulfides.

Carbon nanotubes coupled with layered graphite to support SnTe nanodots as high-rate and ultra-stable lithium-ion battery anodes.

SnTe exhibits a layered crystal structure, which enables fast Li-ion diffusion and easy storage, and is considered to be a promising candidate for an advanced anode material. However, its applications are hindered by the large volume variation caused by intercalation/deintercalation during the electrochemical reaction processes. Herein, topological insulator SnTe and carbon nanotubes (CNTs) supported on a graphite (G) carbon framework (SnTe-CNT-G) were prepared as a new, active and robust anode material for high-rate lithium-ion batteries by a scalable ball-milling method. Remarkably, the SnTe-CNT-G composite used as a lithium-ion battery anode offered an excellent reversible capacity of 840 mA h g-1 at 200 mA g-1 after 100 cycles and high initial coulombic efficiencies of 76.0%, and achieved a long-term cycling stability of 669 mA h g-1 at 2 A g-1 after 1400 cycles. The superior electrochemical performance of SnTe-CNT-G is attributed to the stable design of its electrode structure and interesting topological transition of SnTe, combined with multistep conversion and alloying processes. Furthermore, in situ X-ray diffraction and ex situ X-ray photoelectron spectroscopy were employed to study the reaction mechanism. The results presented here provide new insights to design and reveal the reaction mechanisms of transition metal telluride materials in various energy-storage materials.

Correction: MoS2 nanoflowers encapsulated into carbon nanofibers containing amorphous SnO2 as an anode for lithium-ion batteries.

Correction for 'MoS2 nanoflowers encapsulated into carbon nanofibers containing amorphous SnO2 as an anode for lithium-ion batteries' by Huanhui Chen et al., Nanoscale, 2019, 11, 16253-16261.

MoS2 nanoflowers encapsulated into carbon nanofibers containing amorphous SnO2 as an anode for lithium-ion batteries.

SnO2 with high abundance, large theoretical capacity, and nontoxicity is considered to be a promising candidate for use as advanced electrodes. However, the poor electronic conductivity and large volume variations hinder the practical applications of SnO2-based electrodes for use in lithium-ion batteries (LIBs). Herein, the MoS2-SnO2 heterostructures were encapsulated into carbon nanofibers (CNFs) via facile solvothermal and electrospinning methods. Remarkably, when the binder-free and robust MoS2-SnO2@CNF is employed as the anode for LIBs, such a clever structure yields a discharge capacity of 983 mA h g-1 at a current density of 200 mA g-1 after 100 cycles and a capacity of 710 mA h g-1 after 800 cycles at a current density of 2000 mA g-1. Moreover, full cells and flexible full cells were constructed, which exhibited high flexibility and delivered a high reversible capacity of 463 mA h g-1 after 100 cycles at 500 mA g-1. The exceptional performance of MoS2-SnO2@CNF could be attributed to the rational design of the electrode structure. On one hand, the robust structure of the amorphous SnO2 and MoS2 nanoflowers in the conductive carbon network not only provides direct current pathways, but also enhances electron transfer. On the other hand, the abundance of p-n heterogeneous interfaces considerably reduces the charge transfer resistance and enhances the surface reaction kinetics. This work proposes a feasible strategy to enhance the capacity and stability of SnO2-based electrodes and opens up a new avenue for the potential applications of SnO2 anode materials.