In-situ Grown SnS2 Nanosheets on rGO as an Advanced Anode Material for Lithium and Sodium Ion Batteries

Enhanced charge capacity and stability of Germanium(IV) Sulfide-Based anodes through Triton X100-Assisted synthesis and polysulfide shuttle mitigation

Highly soluble germanium oxide,an amorphous macroreticular form of germanium oxide, was used as a precursor for the deposition of GeS2on reduced graphene oxide (rGO) through a low-temperature, wet-chemistry process. Thermal treatment of the solid provided an ultrathin rGO - supported amorphous GeS2coating. The GeS2@rGO composite was tested as a lithium ion battery (LIB) anode. Leveraging the versatility of wet chemistry processing, we employed strategies initially developed for mitigating polysulfide shuttle effects in lithium-sulfur batteries to enhance anode performance. The anode exhibited exceptional stability, surpassing 1000 cycles, with charge capacities exceeding 1220 and 870 mAh.g-1 at rates of 2 and 5 A.g-1, respectively. Performance improvements were achieved by minimizing GeS2 grain size using the non-ionic surfactant Triton X-100 during synthesis and preventing polysulfide shuttle effects through a negatively charged thick glass fiber separator, fluoroethylene carbonate additive (FEC) in EC:DEC (ethylene carbonate: diethyl carbonate) solvent, and a polyacrylic acid (PAA) binder. These cumulative modifications more than tripled the charge capacity of the germanium sulfide LIB anode. Feasibility was further demonstrated through full cell studies using a LiCoO2 counter electrode.

NiCo2O4@SnS2nanosheets on carbon cloth as efficient bi-functional material for high performance supercapacitor and sensor applications

Bi-functional materials provide an opportunity for the development of high-performance devices. Up till now, bi-functional performance of NiCo2O4@SnS2nanosheets is rarely investigated. In this work, NiCo2O4@SnS2nanosheets were synthesized on carbon cloth by utilizing a simple hydrothermal technique. The developed electrode (NiCo2O4@SnS2/CC) was investigated for the detection of L-Cysteine and supercapacitors applications. As a non-enzymatic sensor, the electrode proved to be highly sensitive for the detection of L-cysteine. The electrode exhibits a reproducible sensitivity of 4645.82μA mM-1cm-2in a wide linear range from 0.5 to 5 mM with a low limit of detection (0.005μM). Moreover, the electrode shows an excellent selectivity and long-time stability. The high specific surface area, enhanced kinetics, good synergy and distinct architecture of NiCo2O4@SnS2nanosheets produce a large number of active sites with substantial energy storage potential. As a supercapacitor, the electrode exhibits improve capacitance of 655.7 F g-1at a current density of 2 A g-1as compare to NiCo2O4/CC (560 F g-1). Moreover, the electrode achieves 95.3% of its preliminary capacitance after 10 000 cycles at 2 A g-1. Our results show that NiCo2O4@SnS2/CC nanosheets possess binary features could be attractive electrode material for the development of non-enzymatic biosensors as well as supercapacitors.

Bio-inspired sustainable synthesis of novel SnS2/biochar nanocomposite for adsorption coupled photodegradation of amoxicillin and congo red: Effects of reaction parameters, and water matrices

This study aims to fabricate a novel integrated photocatalytic adsorbent (IPA) via a green solvothermal process employing tea (Camellia sinensis var. assamica) leaf extract as a stabilizing and capping agent for the removal of organic pollutants from wastewater. An n-type semiconductor photocatalyst, SnS_2, was chosen as a photocatalyst due to its remarkable photocatalytic activity supported over areca nut (Areca catechu) biochar for the adsorption of pollutants. The adsorption and photocatalytic properties of fabricated IPA were examined by taking amoxicillin (AM) and congo red (CR) as two emerging pollutants found in wastewater. Investigating synergistic adsorption and photocatalytic properties under varying reaction conditions mimicking actual wastewater conditions marks the novelty of the present research. The support of biochar for the SnS₂ thin films induced a reduction in charge recombination rate, which enhanced the photocatalytic activity of the material. The adsorption data were in accordance with the Langmuir nonlinear isotherm model, indicating monolayer chemosorption with the pseudo-second-order rate kinetics. The photodegradation process follows pseudo-first-order kinetics with the highest rate constant of 0.0450 min^-1 for AM and 0.0454 min^-1 for CR. The overall removal efficiency of 93.72 ± 1.19% and 98.43 ± 1.53% could be achieved within 90 min for AM and CR via simultaneous adsorption and photodegradation model. A plausible mechanism of synergistic adsorption and photodegradation of pollutants is also presented. The effect of pH, Humic acid (HA) concentration, inorganic salts and water matrices have also been included.The photodegradation activity of SnS₂ under visible light coupled with the adsorption capability of the biochar results in the excellent removal of the contaminants from the liquid phase.

Synthesis and Applications of Dimensional SnS2 and SnS2/Carbon Nanomaterials

Dimensional nanomaterials can offer enhanced application properties benefiting from their sizes and morphological orientations. Tin disulfide (SnS₂) and carbon are typical sources of dimensional nanomaterials. SnS₂ is a semiconductor with visible light adsorption properties and has shown high energy density and long cycle life in energy storage processes. The integration of SnS₂ and carbon materials has shown enhanced visible light absorption and electron transmission efficiency. This helps to alleviate the volume expansion of SnS₂ which is a limitation during energy storage processes and provides a favorable bandgap in photocatalytic degradation. Several innovative approaches have been geared toward controlling the size, shape, and hybridization of SnS₂/Carbon composite nanostructures. However, dimensional nanomaterials of SnS₂ and SnS₂/Carbon have rarely been discussed. This review summarizes the synthesis methods of zero-, one-, two-, and three-dimensional SnS₂ and SnS₂/Carbon composite nanomaterials through wet and solid-state synthesis strategies. Moreover, the unique properties that promote their advances in photocatalysis and energy conversion and storage are discussed. Finally, some remarks and perspectives on the challenges and opportunities for exploring advanced SnS₂/Carbon nanomaterials are presented.

Recent Developments of Tin (II) Sulfide/Carbon Composites for Achieving High-Performance Lithium Ion Batteries: A Critical Review

The ever-increasing worldwide energy demand and the limited resources of fossil have forced the urgent adoption of renewable energy sources. Additionally, concerns over CO₂ emissions and potential increases in fuel prices have boosted technical efforts to make hybrid and electric vehicles more accessible to the public. Rechargeable batteries are undoubtedly a key player in this regard, especially lithium ion batteries (LIBs), which have high power capacity, a fast charge/discharge rate, and good cycle stability, while their further energy density improvement has been severely limited, because of the relatively low theoretical capacity of the graphite anode material which is mostly used. Among various high-capacity anode candidates, tin (II) sulfide (SnS₂) has been attracted remarkable attention for high-energy LIBs due to its enormous resource and simplicity of synthesis, in addition to its high theoretical capacity. However, SnS₂ has poor intrinsic conductivity, a big volume transition, and a low initial Coulombic efficiency, resulting in a short lifespan. SnS₂/carbon composites have been considered to be a most promising approach to addressing the abovementioned issues. Therefore, this review summarizes the current progress in the synthesis of SnS₂/carbon anode materials and their Li-ion storage properties, with special attention to the developments in Li-based technology, attributed to its immense current importance and promising prospects. Finally, the existing challenges within this field are presented, and potential opportunities are discussed.

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.

Free-Standing SnO2@rGO Anode via the Anti-solvent-assisted Precipitation for Superior Lithium Storage Performance

Metal oxides have been attractive as high-capacity anode materials for lithium-ion batteries. However, oxide anodes encounter drastic volumetric changes during lithium ion storage through the conversion reaction and alloying/dealloying processes, leading to rapid capacity decay and poor cycling stability. Here, we report a free-standing SnO₂@reduced graphene oxide (SnO₂@rGO) composite anode, in which SnO₂ nanoparticles are tightly wrapped within wrinkled rGO sheets. The SnO₂@rGO sheet is assembled in high porosity via an anti-solvent-assisted precipitation of dispersed SnO₂ nanoparticles and graphene oxide sheets in the distilled water, followed by the filtration and post-annealing processes. Significantly enhanced lithium storage performance has been obtained of the SnO₂@rGO anode compared with the bare SnO₂ anode material. A high charge capacity above 700 mAh g^-1 can be achieved with a satisfying 95.6% retention after 50 cycles at a current density of 500 mA g^-1, superior to reserved 126 mAh g^-1 and a much lower 16.8% retention of the bare SnO₂ anode. XRD pattern and HRTEM images of the cycled SnO₂@rGO anode material verify the expected oxidation of Sn to SnO₂ at the fully-charged state in the 50th cycle. In addition, FESEM and TEM images reveal the well-preserved free-standing structure after cycling, which accounts for high reversible capacity and excellent cycling stability of such a SnO₂@rGO anode. This work provides a promising SnO₂-based anode for high-capacity lithium-ion batteries, together with an effective fabrication adoptable to prepare different free-standing composite materials for device applications.

Dendrite-Free Li Metal Plating/Stripping Onto Three-Dimensional Vertical-Graphene@Carbon-Cloth Host

Lithium metal is deemed as an ideal anode material for next-generation lithium ion batteries (LIBs) due to its high specific capacity and low redox potential. However, uncontrolled lithium dendrite formation during electrochemical deposition leads to a low Coulombic efficiency and serious safety issues, dragging metallic lithium anodes out of practical application. One promising strategy to suppress lithium dendrite issues is employing a three-dimensional host with admirable conductivity and large surface area. Herein, a vertical graphene nanosheet grown on carbon cloth (VG/CC) synthesized is adopted as the Li deposition host. The three-dimensional VG/CC with a large surface area can provide abundant active nucleation sites and effectively reduce the current density, leading to homogeneous Li deposition to overcome the dendrite issue. The Li@VG/CC anode exhibits a dendrite-free morphology after a long cycle and superior electrochemical performance to that of planar Cu current collector. It delivers a small voltage hysteresis of 90.9 mV at a high current density of 10 mA cm⁻² and a Coulombic efficiency of 99% over 100 cycles at 2 mA cm⁻². Our results indicate that this all-carbon-based nanostructure host has great potential for next-generation Li metal batteries.

Facile Controlled Synthesis of Spinel LiMn2O4 Porous Microspheres as Cathode Material for Lithium Ion Batteries

Although the electrochemical properties of porous LiMn₂O₄ microspheres are usually improved compared to those of irregular LiMn₂O₄ particles, the effects of the different synthesis conditions on the preparation of the porous LiMn₂O₄ microspheres are rarely discussed in detail. In the present work, porous LiMn₂O₄ microspheres were successfully synthesized by using molten LiOH and porous Mn₂O₃ spheres as a template. Multiple factors were considered in the preparation process, including reagent concentration, pH, adding mode, heating time, etc. The morphology of the MnCO₃ template was crucial for the preparation of porous LiMn₂O₄ microspheres and it was mainly affected by the concentration of reactants and the pH value of the solution during the precipitation process. During the lithiation of Mn₂O₃ microspheres, the heating temperature and the ratio between Mn₂O₃ and lithium salt were the most significant variables in terms of control over the morphology and purity of the LiMn₂O₄ microspheres. Furthermore, we demonstrated that the porous LiMn₂O₄ microspheres presented better rate capability and cyclability compared to commercial LiMn₂O₄ powder as cathode materials for lithium-ion batteries (LIBs). This study not only highlights the shape-controllable synthesis of LiMn₂O₄ microspheres as promising cathode materials, but also provides some useful guidance for the synthesis of porous LiMn₂O₄ microspheres and other LIB' electrode materials.

Heterostructured SnO2-SnS2@C Embedded in Nitrogen-Doped Graphene as a Robust Anode Material for Lithium-Ion Batteries

Tin-based anode materials with high capacity attract wide attention of researchers and become a strong competitor for the next generation of lithium-ion battery anode materials. However, the poor electrical conductivity and severe volume expansion retard the commercialization of tin-based anode materials. Here, SnO₂-SnS₂@C nanoparticles with heterostructure embedded in a carbon matrix of nitrogen-doped graphene (SnO₂-SnS₂@C/NG) is ingeniously designed in this work. The composite was synthesized by a two-step method. Firstly, the SnO₂@C/rGO with a nano-layer structure was synthesized by hydrothermal method as the precursor, and then the SnO₂-SnS₂@C/NG composite was obtained by further vulcanizing the above precursor. It should be noted that a carbon matrix with nitrogen-doped graphene can inhibit the volume expansion of SnO₂-SnS₂ nanoparticles and promote the transport of lithium ions during continuous cycling. Benefiting from the synergistic effect between nanoparticles and carbon matrix with nitrogen-doped graphene, the heterostructured SnO₂-SnS₂@C/NG further fundamentally confer improved structural stability and reaction kinetics for lithium storage. As expected, the SnO₂-SnS₂@C/NG composite exhibited high reversible capacity (1201.2 mA h g⁻¹ at the current rate of 0.1 A g⁻¹), superior rate capability and exceptional long-life stability (944.3 mAh g⁻¹ after 950 cycles at the current rate of 1.0 A g⁻¹). The results demonstrate that the SnO₂-SnS₂@C/NG composite is a highly competitive anode material for LIBs.