Heterogeneous Interface Design for Enhanced Sodium Storage: Sb Quantum Dots Confined by Functional Carbon

Coordination-Assisted Construction of Ultra-Fine Metal Nanoparticle Composites for Stable Sodium-Ion Battery Anodes

Ultra-fine nanoparticles (uf-NPs) embedded in hierarchical porous carbon (HPC) have been proven to possess intriguing properties for various energy storage applications, but effective synthetic control is still lacking. Herein, we present an efficient coordination anchor activation (CAA) strategy for the scalable synthesis and elaborate control of a series of uf-NPs embedded in HPC (Sb@HPC and FeSb2@HPC as examples), which is achieved by taking advantage of the coordination capability of industrial ionic exchange resins. The in situ coordination-anchored uf-NPs and the tailored hierarchical porous HPC enables superior rate capability (533.1 mA h g-1 at 3.30 A g-1 for Sb@HPC, 276.0 mA h g-1 at 5.37 A g-1 for FeSb2@HPC), enhanced cycling stability, and high reversible areal capacity (5.02 mA h cm-2). Our study demonstrates a potentially scalable uf-NP synthesis strategy with industrial raw materials that can be applied to a large variety of energy materials.

2D Bismuth@N-Doped Carbon Sheets for Ultrahigh Rate and Stable Potassium Storage

Metallic Bi, as an alloying-type anode material, has demonstrated tremendous potential for practical application of potassium-ion batteries. However, the giant volume expansion, severe structure pulverization, and sluggish dynamics of Bi-based materials result in unsatisfied rate performance and unstable cycling stability. Here, 2D bismuth@N-doped carbon sheets with BiOC bond and internal void space (2D Bi@NOC) are successfully fabricated via a self-template strategy to address these issues, which own ultrafast electrochemical kinetics and impressive long-term cycling stability for delivering an admirable capacity of 341.7 mAh g^-1 after 1000 cycles at 10 A g^-1 and impressive rate capability of 220.6 mAh g^-1 at 50 A g^-1 . Particularly, the in situ transmission electron microscopy observations visualize the real-time alloying/dealloying process and reveal that plastic carbon shell and void space can availably relieve dramatic volume stress and powerfully maintain structural integrity. Density functional theory calculation and ultraviolet photoelectron spectroscopy test certify that the robust BiOC bond is thermodynamically and kinetically beneficial for adsorption/diffusion of K⁺ . This work will light on designing advanced high-performance energy materials and provide important evidence for understanding the energy storage mechanism of alloy-based materials.

Multidimensional antimony nanomaterials tailored by electrochemical engineering for advanced sodium-ion and potassium-ion batteries

Downsizing the dimensions of materials holds great importance for promoting the alkali-ion storage properties, which is considered to be one of the most efficient methods for improving the cycling stability and rate capability of alloy anodes. Nevertheless, efficient, affordable, and scalable methods to prepare low-dimensional electrode materials are lacking. In this study, we developed a tunable electrochemical strategy for synthesizing multidimensional antimony (Sb) nanomaterials. Depending on different reaction mechanisms in different electrolytes, we fabricated zero-dimensional Sb nanoparticles, two-dimensional (2D) antimonene nanosheets, and a three-dimensional porous Sb network through the electrochemical delamination of bulk Sb in lithium hexafluorophosphate in propylene carbonate, tetraethylammonium hydroxide aqueous solution, and tetraethylammonium hexafluorophosphate in N, N-dimethylformamide, respectively. In the preferred electrolyte, 2D antimonene nanosheets deliver a large sodium storage capacity of 572.5 mAh g^-1 after 200 cycles at 0.2 A g^-1 and an excellent rate capability of 553.6 mAh g^-1 at 5 A g^-1. When used as anode materials for potassium-ion batteries, we obtained a high capacity of 550.3 mAh g^-1 after 300 cycles, and observed a high rate capability of 302.3 mAh g^-1 at 4 A g^-1. These results provide an easy and tunable strategy for designing high-performance low-dimensional materials for next-generation batteries.

Natural Stibnite for Lithium-/Sodium-Ion Batteries: Carbon Dots Evoked High Initial Coulombic Efficiency

The chemical process of local oxidation-partial reduction-deep coupling for stibnite reduction of carbon dots (CDs) is revealed by in-situ high-temperature X-ray diffraction. Sb₂S₃@xCDs anode delivers high initial coulombic efficiency in lithium ion batteries (85.2%) and sodium ion batteries (82.9%), respectively. C-S bond influenced by oxygen-rich carbon matrix can restrain the conversion of sulfur to sulfite, well confirmed by X-ray photoelectron spectroscopy characterization of solid electrolyte interphase layers helped with density functional theory calculations. CDs-induced Sb-O-C bond is proved to effectively regulate the interfacial electronic structure. The application of Sb₂S₃ with marvelous theoretical capacity for alkali metal-ion batteries is seriously limited by its poor electrical conductivity and low initial coulombic efficiency (ICE). In this work, natural stibnite modified by carbon dots (Sb₂S₃@xCDs) is elaborately designed with high ICE. Greatly, chemical processes of local oxidation-partial reduction-deep coupling for stibnite reduction of CDs are clearly demonstrated, confirmed with in situ high-temperature X-ray diffraction. More impressively, the ICE for lithium-ion batteries (LIBs) is enhanced to 85%, through the effect of oxygen-rich carbon matrix on C-S bonds which inhibit the conversion of sulfur to sulfite, well supported by X-ray photoelectron spectroscopy characterization of solid electrolyte interphase layers helped with density functional theory calculations. Not than less, it is found that Sb-O-C bonds existed in the interface effectively promote the electronic conductivity and expedite ion transmission by reducing the bandgap and restraining the slip of the dislocation. As a result, the optimal sample delivers a tremendous reversible capacity of 660 mAh g^-1 in LIBs at a high current rate of 5 A g^-1. This work provides a new methodology for enhancing the electrochemical energy storage performance of metal sulfides, especially for improving the ICE.