Layered-Structure SbPO₄/Reduced Graphene Oxide: An Advanced Anode Material for Sodium Ion Batteries

Abstract

Sodium ion batteries are one of most promising alternatives to lithium ion batteries for large-scale energy storage, due to the high abundance and low cost of sodium in the earth. However, the lack of advanced electrode materials greatly affects their applications. Here, layeredstructure SbPO 4 is explored as an anode material for sodium ion batteries in terms of SbPO 4 nanorods on reduced graphene oxide (SbPO 4 /rGO). In situ transmission electron microscopy images reveal the preferential expansion along the transverse direction of the nanorods upon the first discharging, which arises from the reduction of SbPO 4 to Sb and the subsequent alloying of Sb as supported by in situ X-ray diffraction and selected area electron diffraction patterns. SbPO 4 /rGO exhibits a capacity retention of 99% after 100 cycles at 0.5 A g −1 both in half cells and in full cells. Its specific capacity at 5 A g −1 is 214 mA h g −1 in half cells or 134 mA h g −1 in full cells. Moreover, the energy density of the full cells at 1.2 kW kg −1 total is still 99.8 W h kg −1 total , very promising as an advanced electrode material.

Antimony‐Based Composites Loaded on Phosphorus‐Doped Carbon for Boosting Faradaic Efficiency of the Electrochemical Nitrogen Reduction Reaction

“…TheS b3dc ore level XPS spectrum of the asprepared PC/Sb/SbPO 4 in Figure 2a(plots at the bottom) was deconvoluted into two peaks located at 530.3 eVand 539.7 eV, which can be assigned to Sb 3d 5/2 and Sb 3d 3/2 of SbPO 4 , respectively,c orresponding to the Sb III state. [9] However,n o Sb 0 peaks,w hich should be located at approximately 537.5 and 528.2 eV for Sb 3d 3/2 and Sb 3d 5/2 , [10] are observed, indicating that the metallic Sb is covered by SbPO 4 and is consistent with the HRTEM result. Thes mall peak at ab inding energy (BE) of 531.8 eV can be ascribed to O1s.…”

Self‐Supporting Electrode Composed of SnSe Nanosheets, Thermally Treated Protein, and Reduced Graphene Oxide with Enhanced Pseudocapacitance for Advanced Sodium‐Ion Batteries

“…Further observation from the Figure b, the SnSe nanosheets are consisted of nanocrystals with average particle size of approximately 5 nm. In addition, high‐resolution TEM reveals the ultrathin layer of thermally treated BSA that constitutes hinges bridging between graphene sheets and SnSe nanosheets, and clear lattice fringes of 0.352 and 0.337 nm, corresponding to (201) and (210) planes . Selection‐area electron diffraction (SAED) pattern (in Figure S2) is the faint polycrystalline rings indicating SnSe nanosheet with polycrystalline structure.…”

“…What's more, the ID/IG intensities of grapheme oxide and self-supporting SnSe-TP@rGO film samples are 0.90 and 1.01, respectively, suggesting that the reduction of GO to rGO in composite, consistent well with the XRD results. [38][39] In order to acquire the carbon content in the SnSe-TP@rGO composite, TG analysis is performed from room temperature to 700°C at a ramp of 5°C min À 1 . TG spectra show in Figure 2c, which can be divided into four sections to detail analysis.…”

“…In addition, high-resolution TEM reveals the ultrathin layer of thermally treated BSA that constitutes hinges bridging between graphene sheets and SnSe nanosheets, and clear lattice fringes of 0.352 and 0.337 nm, corresponding to (201) and (210) planes. [38] Selection-area electron diffraction (SAED) pattern (in Figure S2) is the faint polycrystalline rings indicating SnSe nanosheet with polycrystalline structure. At the same time, the EDX elemental mapping (Figure 3e) further indicates homogeneous distributions of the Tin, Selenide, Nitrogen, and Carbon components in composite, demonstrating the uniform coating of thermally treated BSA on SnSe nanosheets.…”

Polyanions Enhance Conversion Reactions for Lithium/Sodium‐Ion Batteries: The Case of SbVO4 Nanoparticles on Reduced Graphene Oxide

“…Generally speaking, this oxidation of Sb happens at the high voltage, which can be easily distinguished by the inflection point in the voltage profile (Figure e). Using SbPO 4 as an example, the voltage plateaus at 1.7 and 0.5 V (vs Na + /Na) in the discharging process come from the reduction of SbPO 4 to metallic Sb and the alloying reaction of Sb . The voltage plateaus at 0.8 and 2.2 V in the charging process originate from the reversed processes, i.e., the dealloying reactions of Na x Sb and the oxidation of Sb to SbPO 4 .…”