Efficient Sodium Storage in Selenium Electrodes Achieved by Selenium Doping and Copper Current Collector Induced Displacement Redox Mechanisms

Abstract

Selenium (Se), with its high specific volume capacity and high electronic and superior kinetics, is considered a promising electrode material with promising applications. However, the solvation and shuttle effects of polyselenides hinder their further application. The selenium/nitrogen-doped hollow porous carbon spheres (Se/NHPCs) are obtained using the sacrificial template and in situ gas-phase selenization methods. The Se species are doped into carbon matrixes in an adjustable amount to form Se-C(N) bonds during this process. Density functional theory calculations show that the Se-C(N) bond enhances the charge transfer between Na 2 Se and carbon matrix and binding energy, which improves rate performance and cycling stability. As expected, Se/NHPCs electrode exhibit high reversible capacity (480 mAh g -1 at 0.5 A g -1 after 200 cycles) and rate performance (311 mAh g -1 at 5 A g -1 ) as the anode for sodium-ion batteries. A series of ex situ characterization results show that Cu 2 Se produced by copper current collector induction is effective in the adsorption of polyselenides while enhancing the electrode conductivity. Since the lattice structures of Cu 2 Se and Na 2 Se are similar, this displacement reaction that does not involve lattice reconfiguration provides an effective strategy for the preparation of high-performance and low-cost electrode materials.

Surface-driven fast sodium storage enabled by Se-doped honeycomb-like macroporous carbon

“…After discharge to 0.01 V, the Se 3d peak visibly shifts toward low binding energy, and a new peak located at 54.3 eV appears, which can be attributed to the formation of Na x Se. 18,20 This result confirms that the doped Se atoms supply additional Na storage sites through redox reactions, leading to the high capacity of the Se-HMC electrodes.…”

“…Se has an electronegativity comparable to S (2.55 for Se and 2.58 for S) and high polarizability, 17 and is an electrochemically active element that can react reversibly with Na + , leading to the formation of Na 2 Se. 18,19 In recent years, several high-capacity Na-Se batteries have been reported based on this electrochemical redox reaction mechanism. 20,21 In addition, Se-doping has been proven to be able to change the state of electron distribution and subsequently improve the electrical conductivity of target materials.…”

Scrutinizing Synergy and Active Site of Nitrogen and Selenium Dual-Doped Porous Carbon for Efficient Triiodide Reduction

“…The quaternary N types in NSeC not only contribute lone-pair electrons to the π-conjugated system but also reduce the ionization energy of the carbon matrix, thereby improving corresponding electronic conductivity and accelerating charge transfer at the catalyst/electrolyte interface . The Se 3d spectrum of NSeC-900 at around 56.3 eV is indexed to the C–Se configuration (Figure b) such as selenophene-Se . These defects such as the N,Se atoms and their vacancies within NSeC will result in the formation of potential active sites for the I 3 – reduction reaction.…”

“…10 The Se 3d spectrum of NSeC-900 at around 56.3 eV is indexed to the C−Se configuration (Figure 2b) such as selenophene-Se. 26 These defects such as the N,Se atoms and their vacancies within NSeC will result in the formation of potential active sites for the I 3 − reduction reaction. The electronic structures of N and C species in NSeC-900 were further studied by synchrotron X-ray absorption spectroscopy (XAS).…”

Photoassisted Electrochemical Hydrogen Evolution Reaction of MFe2O4@Ultrathin Black Phosphorus Amorphous–Crystalline Interface

“…All electrochemical reactions depend on highly efficient and stable catalysts in the reaction media, such as magnetism and light. − Recently, there is an urgent need to develop high-performance multifunctional catalysts with both optical and electrical properties, which is of great significance to understanding the electrocatalytic reactions from reaction thermodynamics and kinetics. − Compared with noble metals Pt, numerous semiconductors catalysts such as phosphides, nitrides, and oxides have been proposed due to the rapid charge transfer and optimal electronic microstructure, − which has focused on moderating the electronic configuration of semiconductor catalysts to further improve PE-HER activity.…”