Honglei Shuai

Bio: Honglei Shuai is an academic researcher from Central South University. The author has contributed to research in topics: Lithium & Electrolyte. The author has an hindex of 11, co-authored 19 publications receiving 604 citations.

Electrochemical exfoliation of graphene-like two-dimensional nanomaterials

Abstract: Unlike zero-dimensional quantum dots, one-dimensional nanowires/nanorods, and three-dimensional networks or even their bulk counterparts, the charge carriers in two-dimensional (2D) materials are confined along the thickness while being allowed to move along the plane. They have distinct characteristics like strong quantum confinement, tunable thickness, and high specific surface area, which makes them a promising candidate in a wide range of applications such as electronics, topological spintronic devices, energy storage, energy conversion, sensors, biomedicine, catalysis, and so on. After the discovery of the extraordinary properties of graphene, other graphene-like 2D materials have attracted a great deal of attention. Like graphene, to realize their potential applications, high efficiency and low cost industrial scale methods should be developed to produce high-quality 2D materials. The electrochemical methods usually performed under mild conditions are convenient, controllable, and suitable for mass production. In this review, we introduce the latest and most representative investigations on the fabrication of 2D monoelemental Xenes, 2D transition-metal dichalcogenides, and other important emerging 2D materials such as organic framework (MOF) nanosheets and MXenes through electrochemical exfoliation. The electrochemical exfoliation conditions of the bulk layered materials are discussed. The numerous factors which will affect the quality of the exfoliated 2D materials, the possible exfoliating mechanism and potential applications are summarized and discussed in detail. A summary of the discussion together with perspectives and challenges for the future of this emerging field is also provided in the last section.

Ultrafast Sodium Full Batteries Derived from XFe (X = Co, Ni, Mn) Prussian Blue Analogs.

Abstract: Exploring high-rate electrode materials with excellent kinetic properties is imperative for advanced sodium-storage systems. Herein, novel cubic-like XFe (X = Co, Ni, Mn) Prussian blue analogs (PBAs), as cathodes materials, are obtained through as-tuned ionic bonding, delivering improved crystallinity and homogeneous particles size. As expected, Ni-Fe PBAs show a capacity of 81 mAh g-1 at 1.0 A g-1 , mainly resulting from their physical-chemical stability, fast kinetics, and "zero-strain" insertion characteristics. Considering that the combination of elements incorporated with carbon may increase the rate of ion transfer and improve the lifetime of cycling stability, they are expected to derive binary metal-selenide/nitrogen-doped carbon as anodes. Among them, binary Ni0.67 Fe0.33 Se2 coming from Ni-Fe PBAs shows obvious core-shell structure in a dual-carbon matrix, leading to enhanced electron interactions, electrochemical activity, and "metal-like" conductivity, which could retain an ultralong-term stability of 375 mAh g-1 after 10 000 loops even at 10.0 A g-1 . The corresponding full-cell Ni-Fe PBAs versus Ni0.67 Fe0.33 Se2 deliver a remarkable Na-storage capacity of 302.2 mAh g-1 at 1.0 A g-1 . The rational strategy is anticipated to offer more possibilities for designing advanced electrode materials used in high-performance sodium-ion batteries.

N-Rich carbon-coated Co3S4 ultrafine nanocrystals derived from ZIF-67 as an advanced anode for sodium-ion batteries.

Abstract: Transition metal sulfides (TMSs) have been extensively studied as electrode materials for sodium-ion batteries by virtue of their high theoretical capacity. However, the poor cyclability limits the practical application of TMSs in sodium ion batteries. In this study, N-rich carbon-coated Co3S4 ultrafine nanocrystal (Co3S4@NC) was prepared by utilizing ZIF-67 as a precursor through continuous carbonization and sulfuration processes, exhibiting ultrafine nanocrystals with a diameter of about 5 nm. When utilized as the anode for sodium ion batteries, the nanohybrid material exhibits remarkable cycling performance with a high specific capacity of 420.9 mA h g−1 at the current density of 100 mA g−1 after 100 cycles, indicating that the cycling performance is strengthened by the nitrogen-doped carbon coating. Impressively, the obtained material shows good rate performances with reversible specific capacities of 386.7, 284.0, and 151.2 mA h g−1 at 400, 1000, and 1400 mA g−1, respectively, due to the high surface-capacitance contribution and porous structure inherited from the precursor, which finally results in the increase in infiltration of electrolyte and the accelerating diffusion rate of Na+. This study sheds light on the routes to improve the performance of TMSs@nitrogen-doped carbon nanohybrid materials for sodium ion batteries.

Enhanced Potassium-Ion Storage of the 3D Carbon Superstructure by Manipulating the Nitrogen-Doped Species and Morphology

Abstract: Potassium-ion batteries (PIBs) are attractive for grid-scale energy storage due to the abundant potassium resource and high energy density. The key to achieving high-performance and large-scale energy storage technology lies in seeking eco-efficient synthetic processes to the design of suitable anode materials. Herein, a spherical sponge-like carbon superstructure (NCS) assembled by 2D nanosheets is rationally and efficiently designed for K+ storage. The optimized NCS electrode exhibits an outstanding rate capability, high reversible specific capacity (250 mAh g−1 at 200 mA g−1 after 300 cycles), and promising cycling performance (205 mAh g−1 at 1000 mA g−1 after 2000 cycles). The superior performance can be attributed to the unique robust spherical structure and 3D electrical transfer network together with nitrogen-rich nanosheets. Moreover, the regulation of the nitrogen doping types and morphology of NCS-5 is also discussed in detail based on the experiments results and density functional theory calculations. This strategy for manipulating the structure and properties of 3D materials is expected to meet the grand challenges for advanced carbon materials as high-performance PIB anodes in practical applications.

Metal Organic Framework-Templated Synthesis of Bimetallic Selenides with Rich Phase Boundaries for Sodium-Ion Storage and Oxygen Evolution Reaction.

Abstract: Two-phase or multiphase compounds have been evidenced to exhibit good electrochemical performance for energy applications; however, the mechanism insights into these materials, especially the performance improvement by engineering the high-active phase boundaries in bimetallic compounds, remain to be seen. Here, we report a bimetallic selenide heterostructure (CoSe2/ZnSe) and the fundamental mechanism behind their superior electrochemical performance. The charge redistribution at the phase boundaries of CoSe2/ZnSe was experimentally and theoretically proven. Benefiting from the abundant phase boundaries, CoSe2/ZnSe exerts low Na+ adsorption energy and fast diffusion kinetics for sodium-ion batteries and high activity for oxygen evolution reaction. As expected, excellent sodium storage capability, specifically a superb cyclic stability of up to 800 cycles for the Na3V2(PO4)3∥CoZn-Se full cell, and efficient water oxidation with a small overpotential of 320 mV to reach 10 mA cm–2 were obtained. This work de...

MoS2 Nanosheets Vertically Aligned on Carbon Paper: A Freestanding Electrode for Highly Reversible Sodium Ion Batteries

Abstract: The development of sodium-ion batteries for large-scale applications requires the synthesis of electrode materials with high capacity, high initial Coulombic efficiency (ICE), high rate performance, long cycle life, and low cost. A rational design of freestanding anode materials is reported for sodium-ion batteries, consisting of molybdenum disulfide (MoS2) nanosheets aligned vertically on carbon paper derived from paper towel. The hierarchical structure enables sufficient electrode/electrolyte interaction and fast electron transportation. Meanwhile, the unique architecture can minimize the excessive interface between carbon and electrolyte, enabling high ICE. The as-prepared MoS2@carbon paper composites as freestanding electrodes for sodium-ion batteries can liberate the traditional electrode manufacturing procedure, thereby reducing the cost of sodium-ion batteries. The freestanding MoS2@carbon paper electrode exhibits a high reversible capacity, high ICE, good cycling performance, and excellent rate capability. By exploiting in situ Raman spectroscopy, the reversibility of the phase transition from 2H-MoS2 to 1T-MoS2 is observed during the sodium-ion intercalation/deintercalation process. This work is expected to inspire the development of advanced electrode materials for high-performance sodium-ion batteries.

The Cathode Choice for Commercialization of Sodium-Ion Batteries: Layered Transition Metal Oxides versus Prussian Blue Analogs

Abstract: With the unprecedentedly increasing demand for renewable and clean energy sources, the sodium-ion battery (SIB) is emerging as an alternative or complementary energy storage candidate to the present commercial lithium-ion battery due to the abundance and low cost of sodium resources. Layered transition metal oxides and Prussian blue analogs are reviewed in terms of their commercial potential as cathode materials for SIBs. The recent progress in research on their half cells and full cells for the ultimate application in SIBs are summarized. In addition, their electrochemical performance, suitability for scaling up, cost, and environmental concerns are compared in detail with a brief outlook on future prospects. It is anticipated that this review will inspire further development of layered transition metal oxides and Prussian blue analogs for SIBs, especially for their emerging commercialization.

Single Fe Atom on Hierarchically Porous S, N-Codoped Nanocarbon Derived from Porphyra Enable Boosted Oxygen Catalysis for Rechargeable Zn-Air Batteries.

Abstract: Iron-nitrogen-carbon materials (Fe-N-C) are known for their excellent oxygen reduction reaction (ORR) performance. Unfortunately, they generally show a laggard oxygen evolution reaction (OER) activity, which results in a lethargic charging performance in rechargeable Zn-air batteries. Here porous S-doped Fe-N-C nanosheets are innovatively synthesized utilizing a scalable FeCl3 -encapsulated-porphyra precursor pyrolysis strategy. The obtained electrocatalyst exhibits ultrahigh ORR activity (E1/2 = 0.84 V vs reversible hydrogen electrode) and impressive OER performance (Ej = 10 = 1.64 V). The potential gap (ΔE = Ej = 10 - E1/2 ) is 0.80 V, outperforming that of most highly active bifunctional electrocatalysts reported to date. Furthermore, the key role of S involved in the atomically dispersed Fe-Nx species on the enhanced ORR and OER activities is expounded for the first time by ultrasound-assisted extraction of the exclusive S source (taurine) from porphyra. Moreover, the assembled rechargeable Zn-air battery comprising this bifunctional electrocatalyst exhibits higher power density (225.1 mW cm-2 ) and lower charging-discharging overpotential (1.00 V, 100 mA cm-2 compared to Pt/C + RuO2 catalyst). The design strategy can expand the utilization of earth-abundant biomaterial-derived catalysts, and the mechanism investigations of S doping on the structure-activity relationship can inspire the progress of other functional electrocatalysts.