Controlled Synthesis of Highly Active Nonstoichiometric Tin Phosphide/Carbon Composites for Electrocatalysis and Electrochemical Energy Storage Applications

Abstract

Three types of new-structured phosphorized tin microspheres (Sn−P), phosphorized tin microsphere-carbon (Sn−P−C), and phosphorized tin nanoparticles embedded in interconnected porous carbon microspheres (Sn−P@PCMs) were prepared through a carbothermal reduction-assisted phosphorization strategy. The characterization of the formation mechanism and microstructure of Sn−P, Sn−P−C, and Sn−P@ PCMs composites demonstrated that the controllable evaporation of coordinated phosphorus in the thermally unstable tin phosphide intermediate by accurate thermal treatment contributed to the formation of a ca. 3 wt % P-doped metallic tin structure featuring a nonstoichiometric Sn x P y (y/x = 0.2) core, a Sn-rich phosphorized metallic (y/x = 0.05) shell, and an increased phosphorus concentration from the outer surface to the inner core. The as-prepared phosphorized tin-based composites were applied as counter electrode materials for dye-sensitized solar cells (DSSCs), in which the Sn−P−C counter electrode exhibited the lowest charge transfer resistance of 3.47 Ω and the assembled DSSCs delivered an optimum power conversion efficiency of 8.59%, superior to those of Pt-based cells (6.78 Ω and 7.46%, respectively). The unique bifunctional structure of the Sn x P y conductive core coupled with the phosphorized metallic Sn δ+ (0 < σ < 0.6) electrocatalytic shell accounts for its excellent electrocatalytic activity and electrical conductivity. In addition, the phosphorized tin-based composites were utilized as potential anodic material for lithium-ion batteries, in which the Sn−P@PCMs electrode showed a specific capacity of 743 mAh g −1 at 0.1C after 400 cycles and 435 mAh g −1 at 5C after 30 cycles. The superior Li-ion storage, cyclability, and rate performance of Sn−P@PCMs could be attributed to the incorporation of Sn−P nanoparticles into interconnected porous carbon microspheres that effectively buffered the large volumetric change and enhanced the electronic−ionic conductivity during the lithiation and delithiation process.

Self-Catalyzed Synthesis of Length-Controlled One-Dimensional Nickel Oxide@N-Doped Porous Carbon Nanostructures from Metal Ion Modified Nitrogen Heterocycles for Efficient Lithium Storage

“…To achieve larger specific capacities and higher rate performances of next generation LIBs, great efforts have been devoted to seeking highly efficient anode alternatives with superior electrochemical activity and extraordinary electronic conductivity . Several types of representative anode materials with high theoretical capacity, earth abundance, low cost and environmental benignity (e.g., metal nitrides, oxides, chalcogenides, alloys, and carbon allotropes) have caught tremendous attention. − Moreover, the combination of carbon nanotubes with metal oxide initiates special interest due to their large surface area, excellent electronic conductivity, and high structural stability. , …”

Heterogeneous Ni3P/Ni nanoparticles with optimized Ni active sites anchored in N-doped mesoporous nanofibers for boosting pH-universal hydrogen evolution

“…As is known to all, transition metal phosphides (TMPs), as a class of interstitial compounds, have become remarkably representative non-noble metal HER electrocatalysts featuring unique crystal structures, excellent electrical conductivities and electrochemical properties. 8,[15][16][17][18][19] Nickel phosphide (Ni x P y ) is one of the most promising candidates among TMPs, displaying extensive application prospects in supercapacitors, 20 photocatalytic degradation, 21 lithium-ion batteries, 22 electrocatalysis, 23 etc. Until now, more than ten stoichiometric compo-sitions of nickel phosphides have been reported, such as NiP, 24 Ni 2 P, 25,26 Ni 5 P 4 , 18 Ni 12 P 5 23 and so on.…”

Hierarchical pompon-like cobalt phosphide as a platinum-free electrocatalyst for dye-sensitized solar cells

“…21,27,28 On the other hand, transition metal phosphides (TMPs) were also reported as the earth abundant and high performance electrocatalyst for multiple electrochemical devices. 7,[29][30][31] To date, Co x Se y -based and TMP-based electrodes rendered up to 10.46% 32 and 9.76% 7 of solar-to-electricity conversion efficiency to their DSSCs. These high records inspired us to explore cobalt phosphide (CoP) as the electrocatalyst for I 3 À reduction due to its good bulk conductivity, appropriate density of states, tunable particle morphology, and low toxicity.…”