Atomic Layer Deposition of Alumina Coatings onto SnS2 for Lithium-Ion Battery Applications

Enhanced Piezoelectric Output Performance of the SnS2/SnS Heterostructure Thin-Film Piezoelectric Nanogenerator Realized by Atomic Layer Deposition

Recently, the inherent piezoelectric properties of the 2D transition-metal dichalcogenides (TMDs) tin monosulfide (SnS) and tin disulfide (SnS₂) have attracted much attention. Thus the piezoelectricity of these materials has been theoretically and experimentally investigated for energy-harvesting devices. However, the piezoelectric output performance of the SnS₂- or SnS-based 2D thin film piezoelectric nanogenerator (PENG) is still relatively low, and the fabrication process is not suitable for practical applications. Here we report the formation of the SnS₂/SnS heterostructure thin film for the enhanced output performance of a PENG using atomic layer deposition (ALD). The piezoelectric response of the heterostructure thin film was increased by ∼40% compared with that of the SnS₂ thin film, attributed to large band offset induced by the heterojunction formation. Consequently, the output voltage and current density of the heterostructure PENG were 60 mV and 11.4 nA/cm² at 0.6% tensile strain, respectively. In addition, thickness-controllable large-area uniform thin-film deposition via ALD ensures that the reproducible output performance is achieved and that the output density can be lithographically adjusted depending on the applications. Therefore, the SnS₂/SnS heterostructure PENG fabricated in this work can be employed to develop a flexible energy-harvesting device or an attachable self-powered sensor for monitoring pulse and human body movement.

Improved performances of lithium-ion batteries by conductive polymer modified copper current collector

Copper current collector coated with conductive polymer by electrochemical polymerization improves the capacity and long-life of LIBs.

Promising Dual-Doped Graphene Aerogel/SnS2 Nanocrystal Building High Performance Sodium Ion Batteries

We report the effort in designing layered SnS₂ nanocrystals decorated on nitrogen and sulfur dual-doped graphene aerogels (SnS₂@N,S-GA) as anode material of SIBs. The optimized mass loading of SnS₂ along with the addition of nitrogen and sulfur on the surface of GAs results in enhanced electrochemical performance of SnS₂@N,S-GA composite. In particular, the introduction of nitrogen and sulfur heteroatoms could provide more active sites and good accessibility for Na ions. Moreover, the incorporation of the stable SnS₂ crystal structure within the anode results in the superior discharge capacity of 527 mAh g^-1 under a current density of 20 mA g^-1 upon 50 cycles. It maintains 340 mAh g^-1 even the current density is increased to 800 mA g^-1. Aiming to further systematically study mechanism of composite with improved SIB performance, we construct the corresponding models based on experimental data and conduct first-principles calculations. The calculated results indicate the sulfur atoms doped in GAs show a strong bridging effect with the SnS₂ nanocrystals, contributing to build robust architecture for electrode. Simultaneously, heteroatom dual doping of GAs shows the imperative function for improved electrical conductivity. Herein, first-principles calculations present a theoretical explanation for outstanding cycling properties of SnS₂@N,S-GA composite.

A versatile strategy for ultrathin SnS2 nanosheets confined in a N-doped graphene sheet composite for high performance lithium and sodium-ion batteries

Ultrathin SnS₂ nanosheets confined in N-doped graphene sheets composite is synthesized by using a simple thermal decomposition method and as excellent electrodes for lithium/sodium-ion batteries.

Novel Mesoporous Flowerlike Iron Sulfide Hierarchitectures: Facile Synthesis and Fast Lithium Storage Capability

The 3D flowerlike iron sulfide (F-FeS) is successfully synthesized via a facile one-step sulfurization process, and the electrochemical properties as anode materials for lithium ion batteries (LIBs) are investigated. Compared with bulk iron sulfide, we find that the unique structural features, overall flowerlike structure, composed of several dozen nanopetals and numerous small size iron sulfide particles embedded within the fine nanopetals, and hierarchical pore structure features provide signification improvements in lithium storage performance, with a high-rate discharge capacity of 779.0 mAh g⁻¹ at a rate of 5 A g⁻¹, due to effectively alleviating the volume expansion during the lithiation/delithiation process, and shorting the diffusion length of both lithium ion and electron. Especially, an excellent cycling stability are achieved, a high discharge capacity of 890 mAh g⁻¹ retained at a rate of 1.0 A g⁻¹, suggesting its promising applications in lithium ion batteries (LIBs).

Recent Progresses and Development of Advanced Atomic Layer Deposition towards High-Performance Li-Ion Batteries

Electrode materials and electrolytes play a vital role in device-level performance of rechargeable Li-ion batteries (LIBs). However, electrode structure/component degeneration and electrode-electrolyte sur-/interface evolution are identified as the most crucial obstacles in practical applications. Thanks to its congenital advantages, atomic layer deposition (ALD) methodology has attracted enormous attention in advanced LIBs. This review mainly focuses upon the up-to-date progress and development of the ALD in high-performance LIBs. The significant roles of the ALD in rational design and fabrication of multi-dimensional nanostructured electrode materials, and finely tailoring electrode-electrolyte sur-/interfaces are comprehensively highlighted. Furthermore, we clearly envision that this contribution will motivate more extensive and insightful studies in the ALD to considerably improve Li-storage behaviors. Future trends and prospects to further develop advanced ALD nanotechnology in next-generation LIBs were also presented.