Tin Phosphide Research Articles

Novel design of Sn4P3@NxC electrodes and their electrochemical properties

Tin phosphide (SnxPy) is recognized as one of the most promising anode materials for lithium-ion batteries due to its exceptionally high theoretical capacity. However, its application is hampered by significant volume expansion during charge-discharge cycles and inferior electrical conductivity. Proper structural design plays a pivotal role in addressing these challenges, paving the way for high-performance anode materials. This study introduces a nitrogen-doped carbon-coated Sn4P3 nanosphere with a core-shell structure, employing dopamine as the nitrogen source. This innovative approach, utilizing template removal and solid-phase phosphorization, results in both the core and shell acting as active materials, thereby enhancing the volumetric energy density of the electrode. The internal voids within the shell layer mitigate volume expansion during charge-discharge cycles, while the presence of the nitrogen-doped carbon layer maintains the material's stability throughout cycling and improves its electrical conductivity. Electrochemical performance tests confirm this material's outstanding energy storage capability, with an initial Coulombic efficiency reaching up to 73.6 %. Furthermore, it maintains a stable capacity of 585 mAh g−1 after 1200 cycles at a current density of 2 A g−1. This research offers a design paradigm for developing novel energy storage materials.

Novel in-situ encapsulation of tin phosphide particles in MXene conductive networks as anode materials of the durable sodium-ion battery

Sodium-ion battery (SIB) is one of potential alternatives to lithium-ion battery, because of abundant resources and lower price of sodium. High electrical conductivity and long-term durability of MXene are advantageous as the anode material of SIB, but low energy density restricts applications. Tin phosphide possesses high theoretical capacity, low redox potential, and large energy density, but volume expansion reduces its cycling stability. In this study, tin phosphide particles are in-situ encapsulated into MXene conductive networks (SnxPy/MXene) by hydrothermal and phosphorization processes as novel anode materials of SIB. MXene amounts and hydrothermal durations are investigated to evenly distribute SnxPy in MXene. After 100 cycles, SnxPy/MXene reaches high specific capacities of 438.8 and 314.1 mAh/g at 0.2 and 1.0 A/g, respectively. The capacity retentions of 6.0% and 73.6% at 0.2 A/g are respectively obtained by SnxPy and SnxPy/MXene. The better specific capacity and cycling stability of SnxPy/MXene are attributed to less volume expansion of SnxPy during charge/discharge processes and relieved self-stacking of MXene by encapsulating SnxPy particles between MXene layers. Electrochemical impedance spectroscopy and Galvanostatic intermittent titration technique are also applied to analyze the charge storage mechanism in SIB. Higher sodium ion diffusion coefficient and smaller charge-transfer resistance are obtained by SnxPy/MXene.

WITHDRAWN: Novel design of Sn4P3@NxC electrodes and their electrochemical properties

Tin phosphide (SnxPy) is recognized as one of the most promising anode materials for lithium-ion batteries due to its exceptionally high theoretical capacity. However, its application is hampered by significant volume expansion during charge-discharge cycles and inferior electrical conductivity. Proper structural design placs a pivotal role in addressing these challenges, paving the way for high-performance anode materials. This study introduces a nitrogen-doped carbon-coated Sn4P3 nanosphere with a core-shell structure, employing dopamine as the nitrogen source. This innovative approach, utilizing template removal and solid-phase phosphorization, results in both the core and shell acting as active materials, thereby enhancing the volumetric energy density of the electrode. The internal voids within the shell layer mitigate volume expansion during charge-discharge cycles, while the presence of the nitrogen-doped carbon layer maintains the material's stability throughout cycling and improves its electrical conductivity. Electrochemical performance tests confirm the outstanding energy storage capability of this material, with an initial Coulombic efficiency reaching up to 73.6 %. Furthermore, it maintains a stable capacity of 585 mAh g^-1 after 1200 cycles at a current density of 2 A g^-1. This research offers a design paradigm for the development of novel energy storage materials.

Study on Tin-Cobalt Bimetallic Phosphide Nanoparticles as a Negative Electrode of Sodium-Ion Batteries.

Tin phosphide (Sn4P3) holds great promise because sodium-ion batteries use this material as an anode with impressive theoretical capacity. In this paper, it is reported that Co-doped Sn4P3 is embedded into carbon-based materials and SnCoP/C with a porous skeleton is prepared. As a result, SnCoP/C-2, as the material utilized in sodium-ion battery anodes, exhibits reversible capacities at 415.6, 345.9, and 315.6 mAh g-1 at current intensities of 0.5, 1.0, and 2.0 A g-1, respectively. The electrochemical reversibility, cycle stability, and rate performance of SnCoP/C samples are obviously better than those of Sn4P3/C. Cobalt in SnCoP/C stabilizes the conductive matrix of tin phosphide and promotes the diffusion kinetics of sodium. These results show that, with an appropriate amount of cobalt doping, highly dispersed nanoparticles can be formed in the tin phosphide matrix, which can significantly enhance the cycle stability of tin-based electrode materials.

Engineering ultra-small tin phosphide encapsulated in 3D phosphorous-doped porous carbon nanosheets as high-performance anodes for lithium-ion batteries

Transition-metal phosphides (TMPs) with high theoretical specific capacity and appropriate reaction potential have been recognized as prospective anode materials for lithium-ion batteries (LIBs). However, the practical application is still hindered by the inferior rate capability and worse cycling stability, which is mainly arising from large volume variations and inferior electric conductivities of TMPs. Herein, ultra-small Sn4P3 particles are fully embedded into three-dimensionally interconnected P-doped porous carbon nanosheets (Sn4P3/P-C@CNs), which is fabricated by a feasible and environmentally friendly synthesis strategy with phytic acid as phosphorus source. The ultra-small Sn4P3 particles and the conductive P-doped 3D carbon backbone is advantage to alleviate the volume changes of Sn4P3 nanoparticles, reduce side reaction with electrolyte and promote the transfer of ions/electrons, leading to a significant improvement in electrochemical performance. Consequently, the Sn4P3/P-C@CNs composite electrode delivers a high reversible capacity of 770 mA h g−1 at 0.1 A/g upon 100 cycles, and exhibits 717 mA h g−1 at 1 A/g after 1000 loops. The lithium storage mechanism is investigated by density functional theory calculations. This research could offer a sensible and facile design strategy for TMPs-based electrode materials and make it hopeful for the applications in next-generation high-energy–density LIBs.

Multi-geometric carbon encapsulated SnP3 composite for superior lithium/potassium ion batteries.

Tin phosphide has gained extensive attention as a prospective anode for lithium/potassium ion batteries because of its high theoretical capacity. Nevertheless, the fast capacity fading, which is induced by the huge volume expansion and poor electrical conductivity during cycling, severely restricts its practical applications. In this work, a SnP3-CNTs/KB composite with a SnP3 content as high as 90 wt% was successfully synthesized by a two-step ball milling method. SnP3 nanoparticles were tightly encapsulated in multi-geometric composite carbon layers to efficiently relieve the volume changes and enhance conductivity. Specifically, the resulting SnP3-CNTs/KB anode showed a specific capacity up to 998.6 mA h g-1 after 100 cycles at 50 mA g-1 and 810.4 mA h g-1 after 500 cycles at 1000 mA g-1 for lithium ion batteries. For potassium ion batteries, a high reversible capacity of 200.2 mA h g-1 was achieved after 200 cycles at 1000 mA g-1. This work affords a new insight for exploring excellent support structures of tin phosphide-based anodes.

Investigation of p-n sensing transition and related highly sensitive NH3 gas sensing behavior of SnPx/rGO composites

Tin phosphides (SnPx) with alternating layers of P and Sn atoms possess abundant acidic P vacancy sites and high electronegativity, which can be potential candidates for gas sensing at room temperatures (RT). Herein, SnPx/rGO composites were fabricated for NH3 gas sensing at RT. Structural characterizations indicated the uniform distribution of SnPx on the rGO surface with small sizes and the existence of abundant acidic P vacancy sites. Gas sensing results showed that the response of SnPx/rGO composites with the phosphating ratio of 1:5 (SG-5) to 40 ppm NH3 at RT can be calculated as 117.5%. Moreover, SG-5 also exhibited a high response to NH3 gas with low concentrations (Response: 3% to 500 ppb NH3) and a LOD of 43.6 ppb. Besides, the NH3-TPD and in situ DRIFTs analysis were conducted to reveal the physical adsorption and complete desorption of NH3 gas on the material surface. More interestingly, due to different adsorption sites and conductive channels, the SnPx/rGO composites exhibited different sensing types upon exposure to reducing and oxidizing gases. Sensing response under different background gas atmospheres indicated that NH3 gases were mainly adsorbed on the heterojunctions to react with the surface oxygen species, exhibiting an n-type sensing behavior. However, NO2 gases were mainly adsorbed on the rGO surface to attract electrons, exhibiting a p-type sensing behavior. Density functional theory calculation results also confirmed the preferred adsorption of NH3 on SnPx and NO2 on rGO surface. This work provides an insight into gas adsorptions and desorptions on the SnPx surface and will promote the applications of metal phosphides in gas sensing.

Sodium-ion diffusion coefficients in tin phosphide determined with advanced electrochemical techniques

Sodium ion insertion plays a critical role in developing robust sodium-ion technologies (batteries and hybrid supercapacitors). Diffusion coefficient values of sodium (DNa+) in tin phosphide between 0.1 V and 2.0 V vs. Na/Na+ are systematically determined by galvanostatic intermittent titration technique (GITT), electrochemical impedance spectroscopy (EIS), and potentiostatic intermittent titration technique (PITT). These values range between 4.55 × 10−12 cm2 s−1 and 1.94 × 10−8 cm2 s−1 and depend on the insertion/de-insertion current and the thickness of the electrode materials. Additionally, DNa+ values differ between the first and second cation insertion because of the solid electrolyte interface (SEI) formation. DNa+ vs. insertion potential alters non-linearly in a “W” form due to the strong interactions of Na+ with tin phosphide particles. The results reveal that GITT is a more appropriate electrochemical technique than PITT and EIS for evaluating DNa+ in tin phosphide.

Synthesis and elucidation of local structure in phase-controlled colloidal tin phosphide nanocrystals from aminophosphines

Aminophosphines are a class of inexpensive, environmentally benign phosphorus precursors that have provided routes to various metal phosphides. In this work, we use the aminophosphine tris(diethyl)aminophosphine to synthesize tin phosphide nanocrystals.

Role of ion beams and their energies in the properties of zinc tin phosphide thin films

Zinc tin phosphide (ZTP) is a promising low cost light sensing semiconductor material. The present study focuses on the effects of various ion beams having energies in the range of keV to MeV, on the structural, optical, and photo-response properties of ZTP thin films. Low energy ions (100 and 200 keV Al and Cu, 150 keV Fe and 60 keV Au ions) of fluences in the range from 1E13 to 1E16 ions/cm2 and high energy ions (80 MeV Si, 100 MeV Ni and 100 MeV Ag ions) from 1E11 to 6E13 ions/cm2 are used. The energy of ions (low or high) determine the changes in the ion-induced defects, structural disorder and recrystallization effects leading to modification in the structural quality, the evolution of microstructure, variation in the optical band gap (from 1.60 to 1.82 eV), and the photo-responsivity to red light up to 0.66 mA/W. The photo-responsivity of the films enhances for 150 keV Fe, 60 keV Au, 80 MeV Si and 100 MeV Ni ions and reduces for 100 and 200 keV Al and Cu and 100 MeV Ag ions. These changes are strongly correlated with the electronic energy loss of the ions in the films. The study demonstrates the applicability of low and high energy ions to improve the photo-response and also reveals the possibility to estimate the extent of its progress in ZTP and other light-sensing materials relevant for photo-detector and solar cell applications.

Atomic Interface Catalytically Synthesizing SnP/CoP Hetero-Nanocrystals within Dual-Carbon Hybrids for Ultrafast Lithium-Ion Batteries

Tin phosphides are attractive anode materials for ultrafast lithium-ion batteries (LIBs) because of their ultrahigh Li-ion diffusion capability and large theoretical-specific capacity. However, difficulties in synthesis and large size enabling electrochemical irreversibility impede their applications. Herein, an in situ catalytic phosphorization strategy is developed to synthesize SnP/CoP hetero-nanocrystals within reduced graphene oxide (rGO)-coated carbon frameworks, in which the SnP relative formation energy is significantly decreased according to density functional theory (DFT) calculations. The optimized hybrids exhibit ultrafast charge/discharge capability (260 mA‧h‧g−1 at 50 A‧g−1) without capacity fading (645 mA‧h‧g−1 at 2 A‧g−1) through 1500 cycles. The lithiation/delithiation mechanism is disclosed, showing that the 4.0 nm sized SnP/CoP nanocrystals possess a very high reversibility and that the previously formed metallic Co of CoP at a relatively high potential accelerates the subsequent reaction kinetics of SnP, hence endowing them with ultrafast charge/discharge capability, which is further verified by the relative dynamic current density distributions according to the finite element analysis.

SnP entangled by carbon nanotube networks as anode for pseudocapacitive half/full battery

Due to the lower operating voltage and higher theoretical specific capacity, tin phosphide is considered a class of materials with prospects as an anode material for lithium-ion batteries (LIBs). Among them, tin monophosphide has attracted people's attention due to its unique layered structure. Unfortunately, because of the challenging synthesis method and metastable nature, the application of SnP is limited. In this work, tin phosphide/carbon nanotubes (SnP/CNTs) are prepared by controlling the nucleation and adjusting the ratio of phosphorus/carbon using carbon nanotube as initiator. Sn-MOF is used as a template to make the morphology of SnP more evenly, and carbon nanotubes can also be used as a conductive network to increase the speed of electron transmission. As an anode material for LIBs, SnP/CNTs reveals superior rate performances (reversible capability of 610 mA·h·g−1 at 2 000 mA·g−1). The full-cell was assembled and tested, after 50 cycles at 0.1 C, the capacity can maintain 292 mA·h·g−1, and its capacity retention rate can reach 80.5%. After 230 cycles, its capacity can maintain at around 223 mA·h·g−1. In addition, SnP/CNTs materials exhibit 89% pseudocapacitance contribution upon cycling, which indicates the robust Li+ storage and satisfactory fast-charging capability. Hence, SnP/CNTs suggests a promising anode material for energy storage system.

Iron and tin phosphide as polymer electrolyte membrane fuel cell cathode catalysts

A new set of catalysts based on metal-phosphorus/nitrogen-carbon, for the electroreduction of molecular oxygen at the polymer electrolyte membrane fuel cell cathode are reported. These catalysts were simply made from folic acid, phosphoric acid, iron or tin oxides. In particular, the tin oxide-based catalyst exhibited superior electrocatalytic activity against state-of-the-art non-platinum-based catalysts with a mass activity of 6 mA mg−1. Successful application of these catalysts at the cathode of a self-breathing fuel cell is also demonstrated, and this validated the suitability of the catalyst to operate under fuel cell conditions. A power density of 12.6 mW cm−2 at ambient condition (25 °C, 20% relative humidity and dry hydrogen) was achieved. This work provides foundation for the emergence of phosphorous based non-platinum catalysts for fuel cell cathodes.

Capacity Fade and Impedance Evolution in Tin Phosphide Anodes for Sodium-Ion Batteries

Sodium-ion batteries (SIBs) offer a potentially more cost effective and environmentally friendly alternative to Lithium-ion batteries for room temperature high density energy storage. To maintain the benefits of SIBs, earth abundance for all the batteries components is paramount. One promising earth abundant anode material for SIBs is tin phosphide (Sn4P3). Tin phosphides are able to retain a high specific capacity for an extended cycle life. Understanding the changes in electrochemistry within a battery as a result of cycling is crucial in the complete understanding of capacity fade mechanisms and subsequent improvement and implementation as an anode material. In this work, the main technique employed to gain this understanding is electrochemical impedance spectroscopy with distribution of relaxation times analysis (EIS-DRT). This mathematical approach to understanding traditional EIS datasets helps distinguish impedance contributions from the following processes: diffusion, counter electrodes, solid electrolyte Interfaces (SEI), and contact resistances.Tin phosphide active material was synthesized by mechanical milling, with material structure confirmed by X-ray diffraction (XRD). Half cells were assembled with sodium counter electrodes and cycled with intermittent EIS assessment. Capacity retention was tracked during cycling to assess electrode operation. EIS-DRT analysis was performed every 5 cycles and after the end of cycling across the anode’s voltage range (0.01-1.5 V vs Na/Na+). After cycling, cyclic voltammetry (CV) and XRD were employed to further understand changes in electrochemical activity and crystal structure associated with the end of cycle life.The evolution of impedance signatures across the initial five cycles exhibits significant shifting within the SEI and counter electrode peak at 1000 Hz. Impedance trends across the voltage range switched, in which lower voltages at higher levels of sodiation exhibit larger impedance contributions to the system. These trends are confirmed by a base understanding of SEI formation and sodiation trends. Relative impedance contributions from the diffusion process increase from pristine to cycled electrodes, with diffusion peaks at becoming the dominant impedance contribution as cycling progresses. Significant changes in DRT trends plateaued after the initial SEI formation over the first five cycles.Abrupt and early failure during cycling of a subset of the cells was marked by a plateau in the working electrode voltage, an increase in contact resistance within EIS-DRT plots and decreased electrochemical activity within CV. Visual post mortem checks correlated well with these findings, with an apparent delamination of the electorate coating from the current collector. Understanding the physical and electrochemical phenomenon within a battery though nondestructive in situ characterization is crucial to simplify work flows in battery testing.

Yolk–shell tin phosphides composites as superior reversibility and stability anodes for lithium/sodium ion batteries

The rational design of nanostructure is crucial to achieving high-rate and long-term cycling performance for electrodes. Herein, the tin phosphide composites with yolk–shell nanostructure (SnxPy/NG) are designed and synthesized by one-step carbonization and phosphorization from the precursor of Sn6O4(OH)4/NG. The SnxPy/NG electrode with yolk–shell nanostructure shows energy storage properties superior to that of nanoclusters or nanoparticles. The void space in yolk–shell nanostructure relieves the huge volume expansion, and the unique phase hybridization of Sn4P3 and SnP0.94 promotes the reaction kinetics. Thus, SnxPy/NG delivers high-rate long-term cycling stability for Li-half cells (521.2 mA h g−1 maintained after 3000 cycles at 5.0 A g−1) and Na-half cells (203.1 mA h g−1 maintained after 300 cycles at 1.0 A g−1). The design strategy can promote the practical application of Sn-based phosphide and pave the way for designing and exploring other metal-based phosphide electrodes for energy storage.

Phase Transformations and Phase Segregation during Potassiation of Sn x P y Anodes.

K-ion batteries (KIBs) have the potential to offer a cheaper alternative to Li-ion batteries (LIBs) using widely abundant materials. Conversion/alloying anodes have high theoretical capacities in KIBs, but it is believed that electrode damage from volume expansion and phase segregation by the accommodation of large K-ions leads to capacity loss during electrochemical cycling. To date, the exact phase transformations that occur during potassiation and depotassiation of conversion/alloying anodes are relatively unexplored. In this work, we synthesize two distinct compositions of tin phosphides, Sn4P3 and SnP3, and compare their conversion/alloying mechanisms with solid-state nuclear magnetic resonance (SSNMR) spectroscopy, powder X-ray diffraction (XRD), and density functional theory (DFT) calculations. Ex situ31P and 119Sn SSNMR analyses reveal that while both Sn4P3 and SnP3 exhibit phase separation of elemental P and the formation of KSnP-type environments (which are predicted to be stable based on DFT calculations) during potassiation, only Sn4P3 produces metallic Sn as a byproduct. In both anode materials, K reacts with elemental P to form K-rich compounds containing isolated P sites that resemble K3P but K does not alloy with Sn during potassiation of Sn4P3. During charge, K is only fully removed from the K3P-type structures, suggesting that the formation of ternary regions in the anode and phase separation contribute to capacity loss upon reaction of K with tin phosphides.

High Performance, Stoichiometric ZnSnP2 Anode for Rechargeable Lithium‐Ion Battery with Concomitant Conversion from Chalcopyrite to Sphalerite Phase

AbstractHerein, we report chalcopyrite phase of zinc tin phosphide (ZnSnP2) as an anode for high rate, rechargeable, lithium‐ion battery. In‐situ Raman spectroscopy reveals the conversion of chalcopyrite phase of ZnSnP2 to a symmetric sphalerite phase upon cycling, which helps in achieving stable and reversible capacity at high discharge rates. This is due to the low bandgap and high conductivity of the sphalerite phase. The in‐situ phase conversion is extremely important as it is difficult to synthesize bulk ZnSnP2 sphalerite phase by the known methods till date. After full phase conversion, a reversible capacity of 750 mAh g−1 is obtained towards the end of 1700 cycles at a rate of 5 A g−1. Full cell assembled using LiCoO2 as the cathode material yields a stable performance with a discharge capacity of around 500 mAh g−1 at 0.5 A g−1 and the rate capability studies demonstrate reversible capacities up to 15 A g−1 current.

Influence of solvation structure on interphase components for tin phosphide anode in potassium-ion batteries

With high theoretical capacity, tin phosphide (Sn 4 P 3 ) has recently garnered attention as the anode for potassium-ion batteries (PIBs). However, its application is limited by the rapid capacity decay, which is highly correlated with the stability of solid electrolyte interphase (SEI). Here, we explore how the solvation structure of electrolytes affects the interphase components for the Sn 4 P 3 anode, thus determining the cycle stability. The decomposition of FSI − and ester solvents, particularly EC, may result in the SEI layer being enriched with poly(CO 3 ) and K-F, leading to a more stable cycling capability of K/Sn 4 P 3 batteries in the KFSI-EC:DMC:EMC electrolyte. Moreover, a compact and uniform SEI layer promotes cycle stability. Theoretical analysis of the solvation structure epitomizes that the KFSI-EC:DMC:EMC electrolyte can generate a stable SEI layer due to K + interacting more with FSI − anions and EC solvent. The finding of this work helps us comprehend how SEI layer components affect the capacity of Sn 4 P 3 anodes in PIBs. • Comparison of Sn 4 P 3 anodes in ester- and ether-based electrolytes for KIBs • Exploration of role of the solvation structure of electrolytes • Theoretical and experimental analysis of SEI layer components The rapid capacity decay of Sn 4 P 3 limits its application in potassium-ion batteries due to the stability of the SEI layer. Theoretical and experimental analyses by Sun et al. reveal that the KFSI-EC:DMC:EMC electrolyte can generate a stable SEI layer, explaining the influence of components and boosting the potential for application of Sn 4 P 3 in potassium-ion batteries.

Growth, Raman Scattering Investigation and Photodetector Properties of 2D SnP.

As an important metal phosphides material, 2D tin phosphides (SnPx 0< x≤3) have been theoretically predicted to have intriguing physicochemical properties and potential applications in electronics, optoelectronics, and energy fields. However, the synthesis of high-quality 2D SnP single crystal has not been reported due to the lack of efficiency and reliable growth method. Here, a facile atmospheric pressure chemical vapor deposition (APCVD) method is developed to realize the growth of high-quality 2D SnP nanosheets, by employing tin (Sn) foil as both liquid metal substrates and reaction precursor. Temperature-dependent and angle-resolved polarization Raman spectra observed Raman peaks located at 142.6, 303.3, and 444.2 cm-1 are concluded to belong to A1g mode, which are consistent with the theoretical calculation results. Moreover, the field-effect transistor (FET) devices based on SnP nanosheets show a typical n-type characteristic with an on/off ratio of 103 at 200 K. SnP nanosheets also demonstrate excellent photoresponse performance under the illumination of 473, 532, and 639nm lasers, which can be tuned by Vgs , Vds , and light power density. It is believed that these findings can provide the first-hand experimental information for the future study of 2D SnP nanosheets.

Engineering unique vesicle structured tin phosphides@P/N co-doped carbon anode for high-performance sodium/lithium-ion batteries

Engineering unique vesicle structured tin phosphides@P/N co-doped carbon anode for high-performance sodium/lithium-ion batteries