Synthesis and Electrochemical Performance of ZnSe Electrospinning Nanofibers as an Anode Material for Lithium Ion and Sodium Ion Batteries

ZnSe/SnSe2 hollow microcubes as cathode for high performance aluminum ion batteries

Advances in cathode material design and understanding of intercalation mechanisms are necessary to improve the overall performance of aluminum ion batteries. Therefore, we designed ZnSe/SnSe₂ hollow microcubes with heterojunction structure as a cathode material for aluminum ion batteries. ZnSe/SnSe₂ hollow microcubes with an average size of about1.4 µm were prepared by selenization of ZnSn(OH)₆ microcubes successfully. The shell thickness of ZnSe/SnSe₂ hollow microcubes is about 250 nm. On one hand, the hollow cubic structure can effectively alleviate the volume effect, provide shorter ion diffusion paths, and increase the contact area with the electrolyte. On the other hand, ZnSe/SnSe₂ heterojunction structure can establish a built-in electric field to facilitate ion transport. The synergistic effect of the two leads to the improved electrochemical performance of ZnSe/SnSe₂ as the cathode of aluminum ion batteries. The material delivered a reversible capacity of 124 mAh/g after 150 cycles at a current density of 100 mA/g. Meanwhile, coulombic efficiency remained above 98% in almost all cycles. In addition, the electrochemical reaction mechanism and kinetic process of Al³⁺ and ZnSe/SnSe₂ were studied.

Phase Conversion Accelerating "Zn-Escape" Effect in ZnSe-CFs Heterostructure for High Performance Sodium-Ion Half/Full Batteries

Sodium-ion batteries (SIBs) are considered as a promising large-scale energy storage system owing to the abundant and low-cost sodium resources. However, their practical application still needs to overcome some problems like slow redox kinetics and poor capacity retention rate. Here, a high-performance ZnSe/carbon fibers (ZnSe-CFs) anode is demonstrated with high electrons/Na⁺ transport efficiency for sodium-ion half/full batteries by engineering ZnSe/C heterostructure. The electrochemical behavior of the ZnSe-CFs heterostructure anode is deeply studied via in situ characterizations and theoretical calculations. Phase conversion is revealed to accelerate the "Zn-escape" effect for the formation of robust solid electrolyte interphase (SEI). This leads to the ZnSe-CFs delivering a superior rate performance of 206 mAh g^-1 at 1500 mA g^-1 for half battery and an initial discharge capacity of 197.4 mAh g^-1 at a current density of 1 A g^-1 for full battery. The work here heralds a promising strategy to synthesize advanced heterostructured anodes for SIBs, and provides the guidance for a better understanding of phase conversion anodes.

MOFs-Derived Flower-Like Hierarchically Porous Zn-Mn-Se/C Composite for Extraordinary Rate Performance and Durable Anode of Sodium-Ion and Potassium-Ion Batteries

The slow kinetics and poor structural stability prevent transition metal selenides from being widely used in sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs). Herein, the "flower-like" porous carbon anchored by Zn-Mn binary selenides (ZMS@FC) composites are fabricated by selenizing the modified hierarchically metal-organic frameworks. The 2D conductive hierarchically flakes' abundant pore structure and multiple active sites shorten the ion diffusion length and promote conductivity, while the synergistic effect of the binary metals and intrinsic large pseudocapacitive contribution effectively improve capacity and rate performance. ZMS@FC composites exhibit impressive rate capability of 294.4 mA h g^-1 at 10 A g^-1 and excellent cyclic stability with 369.6 mA h g^-1 specific capacity retention at 2 A g^-1 after 1000 cycling in SIBs. It is noted that 156.9 mA h g^-1 can be retained at 5 A g^-1 and 227.0 mA h g^-1 is remained after 500 cycles at 2 A g^-1 in PIBs. The ex situ X-ray diffraction patterns and transmission electron microscopy pictures are used to confirm the conversion reaction processes of the Zn-Mn-Se. Designing high-performance energy storage materials may benefit greatly from the universal synthesis technology of bimetallic sulfide anodes for enhanced SIBs and PIBs.

Research progress on ZnSe and ZnTe anodes for rechargeable batteries

Transition-metal chalcogenides (TMCs) with tunable direct bandgaps and interlayer spacing are attractive for energy-related applications. Semiconducting zinc chalcogenides, especially their selenides (ZnSe) and tellurides (ZnTe), with enhanced conductivity, high theoretical capacity, low operation voltage and abundance, have appeared on the horizon and receive increasing interest in terms of electrochemical energy storage and conversion. Despite the existing typical obstruction owing to the large volume change, relatively low electrical conductivity and sluggish ion diffusion kinetics into the bulk phase, several effective strategies such as compositing, doping, nanostructuring, and electrode/cell design have exhibited promising applications. We herein provide a timely and systematic overview of recent research and significant advances regarding ZnSe, ZnTe and their hybrids/composites, covering synthesis to electrode design and to applications, especially in advanced Li/Na/K-ion batteries, as well as the reaction mechanisms thereof. It is hoped that the overview will shed new light on the development of ZnSe and ZnTe for next-generation rechargeable batteries.

Heterogeneous interface-induced electrocatalytic efficiency boosting of bimetallic Cu/Zn selenides for stable water oxidation and oxygen reduction reactions

Low overpotential and high stability of heterostructured bimetallic copper and zinc selenides for OER and ORR.

Fabrication of ZnSe/C Hollow Polyhedrons for Lithium Storage

ZnSe has got extensive attention for high-performance LIBs anode due to its remarkable theoretical capacity and environmental friendliness. Nevertheless, the large volume variation for the ZnSe in the discharge/charge processes brings about rapid capacity fading and poor rate performance. Herein, ZnSe/C hollow polyhedrons are successfully synthesized by selenization of zeolitic imidazolate framework-8 (ZIF-8) with resorcinol-formaldehyde (RF) coating. The protection of C layer derived from RF coating layer and Ostwald ripening during the process of selenization play important roles in promoting formation of ZnSe/C hollow polyhedrons. The ZnSe/C hollow polyhedrons exhibit good rate performance and long-term cycle stability (345 mAh g^-1 up to 1000 cycles at 1 A g^-1 ) for lithium ion batteries (LIBs) anode. The improved electrochemical performance is benefit from the unique ZnSe/C hollow structure, in which the hollow structure can effectively avoid terrible volume expansion, and the thin ZnSe/C shell can not only provide adequate diffusion paths of lithium ions and but also enhance the electronic conductivity.

Electrospun Carbon Nanofibers from Biomass and Biomass Blends-Current Trends

In recent years, ecological issues have led to the search for new green materials from biomass as precursors for producing carbon materials (CNFs). Such green materials are more attractive than traditional petroleum-based materials, which are environmentally harmful and non-biodegradable. Biomass could be ideal precursors for nanofibers since they stem from renewable sources and are low-cost. Recently, many authors have focused intensively on nanofibers' production from biomass using microwave-assisted pyrolysis, hydrothermal treatment, ultrasonication method, but only a few on electrospinning methods. Moreover, still few studies deal with the production of electrospun carbon nanofibers from biomass. This review focuses on the new developments and trends of electrospun carbon nanofibers from biomass and aims to fill this research gap. The review is focusing on recollecting the most recent investigations about the preparation of carbon nanofiber from biomass and biopolymers as precursors using electrospinning as the manufacturing method, and the most important applications, such as energy storage that include fuel cells, electrochemical batteries and supercapacitors, as well as wastewater treatment, CO2 capture, and medicine.

Willow-Leaf-Like ZnSe@N-Doped Carbon Nanoarchitecture as a Stable and High-Performance Anode Material for Sodium-Ion and Potassium-Ion Batteries

ZnSe is regarded as a promising anode material for energy storage due to its high theoretical capacity and environment friendliness. Nevertheless, it is still a significant challenge to obtain superior electrode materials with stable performance owing to the serious volume change and aggregation upon cycling. Herein, a willow-leaf-like nitrogen-doped carbon-coated ZnSe (ZnSe@NC) composite synthesized through facile solvothermal and subsequent selenization process is beneficial to expose more active sites and facilitate the fast electron/ion transmission. These merits significantly enhance the electrochemical performances of ZnSe@NC for sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs). The obtained ZnSe@NC exhibits outstanding rate performance (440.3 mAh g^-1 at 0.1 A g^-1 and 144.4 mAh g^-1 at 10 A g^-1 ) and ultralong cycle stability (242.2 mAh g^-1 at 8.0 A g^-1 even after 3200 cycles) for SIBs. It is noted that 106.5 mAh g^-1 can be retained after 550 cycles and 71.4 mAh g^-1 is still remained after 1500 cycles at 200 mA g^-1 when applied as anode for PIBs, indicating good cycle stability of the electrode. The possible electrochemical mechanism and the ionic diffusion kinetics of the ZnSe@NC are investigated using ex situ X-ray diffraction, high-resolution transmission electron microscopy, and a series of electrochemical analyses.

Cl- Doping Strategy to Boost the Lithium Storage Performance of Lithium Titanium Phosphate

Because of energy storage limitations and the high demand for energy, aqueous rechargeable lithium batteries (ARLBs) are receiving widespread attention due to their excellent performance and high safety. Lithium titanium phosphate (LiTi₂(PO₄)₃) exhibits the potential to serve as anodes for ARLBs because it has a three-dimensional channel and a stable structure. We employed an anion (Cl⁻) doping strategy to boost the lithium storage performance of LiTi₂(PO₄)₃. A series of LiTi₂(PO₄)₃/C composites doped with Cl⁻ on PO43- were successfully synthesized with a sol-gel technique as anodes for ARLBs. The effects of chlorine doping with different content on the properties of LiTi₂(PO₄)_3−xCl_3x/C (x = 0.05, 0.10, and 0.15) were investigated systematically. The doping of chlorine in appropriate amounts did not significantly impact the main structure and morphology of LiTi₂(PO₄)₃/C. However, chlorine doping greatly increased the performance of LiTi₂(PO₄)₃/C. LiTi₂(PO₄)_2.9Cl_0.3/C (LCl-10) showed the best electrochemical properties. It delivered a discharge capacity of 108.5 and 85.5 mAh g⁻¹ at 0.5 and 15°C, respectively, with an increase of 13.2 and 43.3 mAh g⁻¹ compared to blank LiTi₂(PO₄)₃ (LCl). In addition, the discharge capacity of LCl-10 was maintained at 61.3% after 1,000 cycles at 5°C, implying an apparent improvement compared to LCl (35.3%). Our study showed that a chlorine-doped LiTi₂(PO₄)₃/C composite is a potential anode for high-performance ARLBs.

One-Step Microwave Synthesis of Micro/Nanoscale LiFePO4/Graphene Cathode With High Performance for Lithium-Ion Batteries

In this study, micro/nanoscale LiFePO₄/graphene composites are synthesized successfully using a one-step microwave heating method. One-step microwave heating can simplify the reduction step of graphene oxide and provide a convenient, economical, and effective method of preparing graphene composites. The structural analysis shows that LiFePO₄/graphene has high phase purity and crystallinity. The morphological analysis shows that LiFePO₄/graphene microspheres and micron blocks are composed of densely aggregated nanoparticles; the nanoparticle size can shorten the diffusion path of lithium ions and thus increase the lithium-ion diffusion rate. Additionally, the graphene sheets can provide a rapid transport path for electrons, thus increasing the electronic conductivity of the material. Furthermore, the nanoparticles being packed into the micron graphene sheets can ensure stability in the electrolyte during charging and discharging. Raman analysis reveals that the graphene has a high degree of graphitization. Electrochemical analysis shows that the LiFePO₄/graphene has an excellent capacity, high rate performance, and cycle stability. The discharge capacities are 166.3, 156.1, 143.0, 132.4, and 120.9 mAh g^-1 at rates of 0.1, 1, 3, 5, and 10 C, respectively. The superior electrochemical performance can be ascribed to the synergy of the shorter lithium-ion diffusion path achieved by LiFePO₄ nanoparticles and the conductive networks of graphene.