Enhanced conversion reaction kinetics in low crystallinity SnO 2 /CNT anodes for Na-ion batteries

128

In this work, an ether‐based electrolyte is adopted instead of conventional ester‐based electrolyte for an Sb2O3‐based anode and its enhancement mechanism is unveiled for K‐ion storage. The anode is fabricated by anchoring Sb2O3 onto reduced graphene oxide (Sb2O3‐RGO) and it exhibits better electrochemical performance using an ether‐based electrolyte than that using a conventional ester‐based electrolyte. By optimizing the concentration of the electrolyte, the Sb2O3‐RGO composite delivers a reversible specific capacity of 309 mAh g−1 after 100 cycles at 100 mA g−1. A high specific capacity of 201 mAh g−1 still remains after 3300 cycles (111 days) at 500 mA g−1 with almost no decay, exhibiting a longer cycle life compared with other metallic oxides. In order to further reveal the intrinsic mechanism, the energy changes for K atom migrating from surface into the sublayer of Sb2O3 are explored by density functional theory calculations. According to the result, the battery using the ether‐based electrolyte exhibits a lower energy change and migration barrier than those using other electrolytes for K‐ion, which is helpful to improve the K‐ion storage performance. It is believed that the work can provide deep understanding and new insight to enhance electrochemical performance using ether‐based electrolytes for KIBs.

Section: Resultsmentioning

confidence: 78%

K‐Ion Storage Enhancement in Sb₂O₃/Reduced Graphene Oxide Using Ether‐Based Electrolyte

Zhuang

Xie

et al. 2019

128

“…The HNO 3 treatment of PCNFs simultaneously removed the Fe 3 C nanoparticles and oxidized the PCNF surface, as evidenced by the increased intensity of oxygen peak in the X-ray photoelectron spectroscopy (XPS) spectrum ( Figure S4, Supporting Information) and the larger weight loss of PCNF-1.5-HNO 3 than PCNF-1.5-HCl by the thermogravimetric analysis (TGA) ( Figure S5, Supporting Information) due to the removal of oxygenated functional groups. [35] The peak located at 285.5 eV is attributed to the photoelectron of hydroxyl groups, epoxy groups, and N-doping due to the high N content in the PAN precursor [36,37] while the broad peak centered at 288.6 eV represents carboxyl groups in PCNFs. Figure 2c presents the deconvoluted C1s spectra, where the contents of various oxygenated groups were quantitatively determined and the results are plotted in Figure 2d.…”

Section: Fabrication and Characterization Of Porous Carbon Nanofibersmentioning

confidence: 99%

Correlation between Li Plating Behavior and Surface Characteristics of Carbon Matrix toward Stable Li Metal Anodes

Cui

Yao

Ihsan‐Ul‐Haq

et al. 2018

Self Cite

118

anodes. These new anodes promise an almost 100% increase in practical energy density compared to those of conventional LIB counterparts. [3][4][5][6][7][8][9] While developing cathodes for the next-generation batteries has made a significant progress, relatively fewer research efforts have thus far been devoted to Li metal anodes because of the formation of Li dendrites which is considered a critical drawback instigating devastating safety issues of batteries. [10] Along with recent studies on Li plating behaviors, there have been renewed interests in developing Li metal anodes. [11][12][13] In particular, the dendrite-free Li metal anode was made possible by rationally designing the electrolyte composition and electrode morphologies. [14,15] Nevertheless, the current Li metal anodes are far from being viable because of several reasons. Namely, (1) the dendritic Li emerges when the current density raises above the percolation value; (2) the Coulombic efficiencies (CEs) of Li metal anodes are too low to maintain good cyclic stability of batteries; and (3) the design of Li metal anodes is still inadequate, making it difficult to integrate into the existing LIB configurations, such as pouch and cylindrical cells. [12] Most of the strategies currently exercised for dendrite-free Li metal anodes usually fail to resolve all the above mentioned issues. For example, the all-solid-state Li-metal battery requires certain prestress to reduce the interfacial resistance between the solid-state electrolyte and the electrode, but such a prestress is difficult to apply on pouch cells. [16,17] The feasibility of artificial solid electrolyte interphase (SEI) protection on Li foil remains doubtful because the Li foil alone cannot be used as current collector in practical cells due to its hostless nature and huge volume changes during the repeated cycles. [11,18] Among all potential strategies, the incorporation of conductive substrates to function as both the Li host and current collector is considered an ideal approach for further development of practical Li metal anodes. [19] The growth of Li dendrites at high current densities was mitigated by means of reduced local current densities using conductive substrates. [12] Moreover, the conductive substrates also functioned as the current collector, which is compatible with the existing LIB configurations. While copper has been widely studied as the matrix material for hosting Li metal, carbon is considered a more promising candidate than copper Carbonaceous materials are widely employed to host Li for stable and safe Li metal batteries while relatively little effort is devoted to tailoring the surface properties of carbon to facilitate uniform Li plating. Herein, the correlation between Li plating behavior and the surface characteristics of electrospun porous carbon nanofibers (PCNFs) is systemically elucidated through experiments and theoretical calculations. It is revealed that the neat carbon surface suffers from severe lattice mismatch with Li metal, hindering uniform Li plating....

“…[4][5][6][7] In view of the recent studies in developing promising cathode materials, [8,9] one of the critical challenges in promoting the commercialization of SIBs is the lack of suitable anode materials with high capacities and rate capability as well as long-term cyclic performance. [12] Many efforts have been devoted to investigating carbonaceous materials, such as hard carbon, [13] hollow carbon sphere, [14] carbon fiber, [15] as well as metals/metal chalcogenides, like Sn, [16] SnO x , [17] SnO 2 , [18] Bi 0.94 Sb 1.06 S 3, [19] and Sb, [20] as the potential anode materials. [12] Many efforts have been devoted to investigating carbonaceous materials, such as hard carbon, [13] hollow carbon sphere, [14] carbon fiber, [15] as well as metals/metal chalcogenides, like Sn, [16] SnO x , [17] SnO 2 , [18] Bi 0.94 Sb 1.06 S 3, [19] and Sb, [20] as the potential anode materials.…”

Section: Doi: 101002/aenm201602149mentioning

confidence: 99%

“…[25][26][27][28] The anodic scan showed three main peaks located at 0.79, 1.33, and 1.64 V, which can be assigned to reversible formation of Sb, Sb 2 S 3 and extraction of Na + ions from the layered structure, respectively. [27] The (3 of 11) 1602149 wileyonlinelibrary.com electrochemical impedance spectra (EIS) were obtained at a frequency ranging between 100 kHz and 0.1 Hz and the equivalent circuit [18,45] along with the Z-view software simulation results are shown in Figure S3b in the Supporting Information. All resistance parameters, R s , R ct , and W, of the SSNR/C electrode were much smaller than those of the SSNR counterpart, indicating the amorphous carbon coating facilitated fast ion/electronic transfer at the electrode/electrolyte interface, which in turn improved the cyclic and rate performance of the electrodes.…”

Section: Morphology Structure and Electrochemical Performancementioning

confidence: 99%

Unveiling the Unique Phase Transformation Behavior and Sodiation Kinetics of 1D van der Waals Sb₂S₃ Anodes for Sodium Ion Batteries

Yao

Cui

et al. 2016

Self Cite

162

140

systems is hindered by the limited reserves and high cost of lithium. [1][2][3] Compared with LIBs, sodium ion batteries (SIBs) enjoy many advantages, such as low costs arising from abundance of sodium as well as potentially wider applications, including grid energy storage. [4][5][6][7] In view of the recent studies in developing promising cathode materials, [8,9] one of the critical challenges in promoting the commercialization of SIBs is the lack of suitable anode materials with high capacities and rate capability as well as long-term cyclic performance. The commercial graphite anode in LIBs cannot host the Na + ions whose diameter is 34% larger than the Li + ions in the commonly used carbonate-based electrolyte system, [10,11] although a recent study demonstrated the feasibility of cointercalation of Na + ions in ether-based electrolyte upon the formation of a ternary intercalation compound. [12] Many efforts have been devoted to investigating carbonaceous materials, such as hard carbon, [13] hollow carbon sphere, [14] carbon fiber, [15] as well as metals/metal chalcogenides, like Sn, [16] SnO x , [17] SnO 2 , [18] Bi 0.94 Sb 1.06 S 3, [19]and Sb, [20] as the potential anode materials. Compared with carbonaceous anodes possessing low storage capacities and unsafely low working potentials, anodes made from metal sulfides have been increasingly explored to achieve superior rate performance and high specific capacities. [21][22][23][24][25] For example, antimony trisulfide (Sb 2 S 3 ) has drawn significant attention because of its attractive reversible theoretical capacity of 946 mAh g −1 by accommodating 12 moles of Na + ions per Sb 2 S 3 mole and the improved cyclic performance owing to the Na 2 S phase serving as the buffer matrix to relieve the volume expansion. [26] So far, many methods have been adopted to successfully fabricate various Sb 2 S 3 -based anodes, such as reduced graphene oxide (rGO)/Sb 2 S 3 , [25] flower-like Sb 2 S 3 , [26] Sb 2 S 3graphite, [27] and rod-shaped Sb 2 S 3 , [28] which demonstrated exceptional reversible capacities and great potential for SIBs. However, the fundamental understanding of the underlying sodiation reaction mechanisms is still lacking and needs to be investigated in order to promote the wide application of the Sb 2 S 3 anodes.Carbon-coated van der Waals stacked Sb 2 S 3 nanorods (SSNR/C) are synthesized by facile hydrothermal growth as anodes for sodium ion batteries (SIBs). The sodiation kinetics and phase evolution behavior of the SSNR/C anode during the first and subsequent cycles are unraveled by coupling in situ transmission electron microscopy analysis with first-principles calculations. During the first sodiation process, Na + ions intercalate into the Sb 2 S 3 crystals with an ultrafast speed of 146 nm s −1 . The resulting amorphous Na x Sb 2 S 3 intermediate phases undergo sequential conversion and alloying reactions to form crystalline Na 2 S, Na 3 Sb, and minor metallic Sb. Upon desodiation, Na + ions extract from the nanocrystalline phases to leave behi...