In Situ Hybridization Strategy Constructs Heterogeneous Interfaces to Form Electronically Modulated MoS2/FeS2 as the Anode for High-Performance Lithium-Ion Storage.

The interfacial effect is important for anodes of transition metal dichalcogenides (TMDs) to achieve superior lithium-ion storage performance. In this paper, a MoS2/FeS2 heterojunction is synthesized by a simple hydrothermal reaction to construct the interface effect, and the heterostructure introduces an inherent electric field that accelerates the de-embedding process of lithium ions, improves the electron transfer capability, and effectively mitigates volume expansion. XPS analysis confirms evident chemical interaction between MoS2 and FeS2 via an interfacial covalent bond (Mo-S-Fe). This MoS2/FeS2 anode shows a distinct interfacial effect for efficient interatomic electron migration. The electrochemical performance demonstrated that the discharge capacity can reach up to 1217.8 mA h g-1 at 0.1 A g-1 after 200 cycles, with a capacity retention rate of 72.9%. After 2000 cycles, the capacity retention is about 61.6% at 1.0 A g-1, and the discharge capacity can still reach 638.9 mA h g-1. Electrochemical kinetic analysis indicated an enhanced pseudocapacitance contribution and that the MoS2/FeS2 had sufficient adsorption of lithium ions. This paper therefore argues that this interfacial engineering is an effective solution for designing sulfide-based anodes with good electrochemical properties.

Pre-lithiation strategy to design a high-performance zinc oxide anode for lithium-ion batteries.

Zinc oxide (ZnO) shows great potential as an anode material for advanced energy storage devices owing to its good structural stability and low cost. However, its inferior cycling capacity seriously restricts its practical application. In this work, a pre-lithiation strategy is adopted to construct pre-lithiated ZnO (Li-ZnO) via the facile solid-state reaction method. This well-designed Li-ZnO is polycrystalline, consisting of fine particles. XPS analysis and Raman results confirm the successful pre-lithiation strategy. The pre-lithiation strategy increases the electronic conductivity of Li-ZnO without further carbon coating and suppresses the volume expansion during the electrochemical reaction. As a result, 5 mol% Li-ZnO displays good reversible capacity with a specific capacity of 639 mA h g-1 after 200 cycles at 0.1 A g-1. After 1440 cycles at 1.0 A g-1, the capacity retention is 380 mA h g-1. The pseudocapacitance contribution can reach up to 72.5% at 1.0 mV s-1. Electrochemical kinetic analysis shows that this pre-lithiation strategy can accelerate the lithium-ion diffusion and charge transfer kinetics of the Li-ZnO anode and suppress the pulverization of the electrochemical reaction. This study demonstrates the necessity of developing new anode materials with good cycling stability via this pre-lithiation strategy.