Metallic tin has been considered as one of the most promising anode materials both for lithium (LIBs) and sodium ion battery (NIBs) because of a high theoretical capacity and an appropriate low ...discharge potential. However, Sn anodes suffer from a rapid capacity fading during cycling due to pulverization induced by severe volume changes. Here we innovatively synthesized pipe-wire TiO2–Sn@carbon nanofibers (TiO2–Sn@CNFs) via electrospinning and atomic layer deposition to suppress pulverization-induced capacity decay. In pipe-wire TiO2–Sn@CNFs paper, nano-Sn is uniformly dispersed in carbon nanofibers, which not only act as a buffer material to prevent pulverization, but also serve as a conductive matrix. In addition, TiO2 pipe as the protection shell outside of Sn@carbon nanofibers can restrain the volume variation to prevent Sn from aggregation and pulverization during cycling, thus increasing the Coulombic efficiency. The pipe-wire TiO2–Sn@CNFs show excellent electrochemical performance as anodes for both LIBs and NIBs. It exhibits a high and stable capacity of 643 mA h/g at 200 mA/g after 1100 cycles in LIBs and 413 mA h/g at 100 mA/g after 400 cycles in NIBs. These results would shed light on the practical application of Sn-based materials as a high capacity electrode with good cycling stability for next-generation LIBs and NIBs.
Grid-scale energy storage is essential for reliable electricity transmission and renewable energy integration. Redox flow batteries (RFB) provide affordable and scalable solutions for stationary ...energy storage. However, most of the current RFB chemistries are based on expensive transition metal ions or synthetic organics. Here, we report a reversible chlorine redox flow battery starting from the electrolysis of aqueous NaCl electrolyte and the as-produced Cl
is extracted and stored in the carbon tetrachloride (CCl
) or mineral spirit flow. The immiscibility between the CCl
or mineral spirit and NaCl electrolyte enables a membrane-free design with an energy efficiency of >91% at 10 mA/cm
and an energy density of 125.7 Wh/L. The chlorine flow battery can meet the stringent price and reliability target for stationary energy storage with the inherently low-cost active materials (~$5/kWh) and the highly reversible Cl
/Cl
redox reaction.
Engineering a stable solid electrolyte interphase (SEI) is critical for suppression of lithium dendrites. However, the formation of a desired SEI by formulating electrolyte composition is very ...difficult due to complex electrochemical reduction reactions. Here, instead of trial-and-error of electrolyte composition, we design a Li-11 wt % Sr alloy anode to form a SrF2-rich SEI in fluorinated electrolytes. Density functional theory (DFT) calculation and experimental characterization demonstrate that a SrF2-rich SEI has a large interfacial energy with Li metal and a high mechanical strength, which can effectively suppress the Li dendrite growth by simultaneously promoting the lateral growth of deposited Li metal and the SEI stability. The Li–Sr/Cu cells in 2 M LiFSI-DME show an outstanding Li plating/stripping Coulombic efficiency of 99.42% at 1 mA cm–2 with a capacity of 1 mAh cm–2 and 98.95% at 3 mA cm–2 with a capacity of 2 mAh cm–2, respectively. The symmetric Li–Sr/Li–Sr cells also achieve a stable electrochemical performance of 180 cycles at an extremely high current density of 30 mA cm–2 with a capacity of 1 mAh cm–2. When paired with LiFePO4 (LFP) and LiNi0.8Co0.1Mn0.1O2 (NCM811) cathodes, Li–Sr/LFP cells in 2 M LiFSI-DME electrolytes and Li–Sr/NMC811 cells in 1 M LiPF6 in FEC:FEMC:HFE electrolytes also maintain excellent capacity retention. Designing SEIs by regulating Li-metal anode composition opens up a new and rational avenue to suppress Li dendrites.
Abstract
Selective two-electron (2e
−
) oxygen reduction reaction (ORR) offers great opportunities for hydrogen peroxide (H
2
O
2
) electrosynthesis and its widespread employment depends on ...identifying cost-effective catalysts with high activity and selectivity. Main-group metal and nitrogen coordinated carbons (M-N-Cs) are promising but remain largely underexplored due to the low metal-atom density and the lack of understanding in the structure-property correlation. Here, we report using a nanoarchitectured Sb
2
S
3
template to synthesize high-density (10.32 wt%) antimony (Sb) single atoms on nitrogen- and sulfur-codoped carbon nanofibers (Sb-NSCF), which exhibits both high selectivity (97.2%) and mass activity (114.9 A g
−1
at 0.65 V) toward the 2e
−
ORR in alkaline electrolyte. Further, when evaluated with a practical flow cell, Sb-NSCF shows a high production rate of 7.46 mol g
catalyst
−1
h
−1
with negligible loss in activity and selectivity in a 75-h continuous electrolysis. Density functional theory calculations demonstrate that the coordination configuration and the S dopants synergistically contribute to the enhanced 2e
−
ORR activity and selectivity of the Sb-N
4
moieties.
High‐Energy Aqueous Sodium‐Ion Batteries Jin, Ting; Ji, Xiao; Wang, Peng‐Fei ...
Angewandte Chemie International Edition,
May 17, 2021, Volume:
60, Issue:
21
Journal Article
Peer reviewed
Water‐in‐salt electrolytes (WISE) have largely widened the electrochemical stability window (ESW) of aqueous electrolytes by formation of passivating solid electrolyte interphase (SEI) on anode and ...also absorption of the hydrophobic anion‐rich double layer on cathode. However, the cathodic limiting potential of WISE is still too high for most high‐capacity anodes in aqueous sodium‐ion batteries (ASIBs), and the cost of WISE is also too high for practical application. Herein, a low‐cost 19 m (m: mol kg−1) bi‐salts WISE with a wide ESW of 2.8 V was designed, where the low‐cost 17 m NaClO4 extends the anodic limiting potential to 4.4 V, while the fluorine‐containing salt (2 m NaOTF) extends the cathodic limiting potential to 1.6 V by forming the NaF–Na2O–NaOH SEI on anode. The 19 m NaClO4–NaOTF–H2O electrolyte enables a 1.75 V Na3V2(PO4)3∥Na3V2(PO4)3 full cell to deliver an appreciable energy density of 70 Wh kg−1 at 1 C with a capacity retention of 87.5 % after 100 cycles.
A NaClO4/NaOTF electrolyte was designed for aqueous Na‐ion batteries (ASIBs). The solid electrolyte interphase (SEI) containing NaF–Na2O–NaOH forming on the anode extended the cathodic limiting potential of electrolyte to 1.6 V, and the hydrophobic anions extend the anodic to 4.4 V. A 1.75 V Na3V2(PO4)3∥Na3V2(PO4)3 cell achieved a high energy density of 70 Wh kg−1 with 87.5 % capacity retention after 100 cycles.
The wide applications of rechargeable batteries require state‐of‐the‐art batteries that are sustainable (abundant resource), tolerant to high‐temperature operations, and excellent in delivering high ...capacity and long‐term cycling life. Due to the scarcity and uneven distribution of lithium, it is urgent to develop alternative rechargeable batteries. Herein, an organic compound, azobenzene‐4,4′‐dicarboxylic acid potassium salts (ADAPTS) is developed, with an azo group as the redox center for high performance potassium‐ion batteries (KIBs). The extended π‐conjugated structure in ADAPTS and surface reactions between ADAPTS and K‐ions enable the stable charge/discharge of K‐ion batteries even at high temperatures up to 60 °C. When operated at 50 °C, ADAPTS anode delivers a reversible capacity of 109 mAh g−1 at 1C for 400 cycles. A reversible capacity of 77 mAh g−1 is retained at 2C for 1000 cycles. At 60 °C, the ADAPTS‐based KIBs deliver a high capacity of 113 mAh g−1 with 81% capacity retention at 2C after 80 cycles. The exceptional electrochemical performance demonstrates that ADAPTS is a promising electrode material for high‐temperature KIBs.
An organic anode based on an azo group as the redox center is designed and synthesized for high temperature potassium‐ion batteries. The surface reaction‐controlled mechanism between the azo compound and K‐ions enables superior electrochemical performance of K‐ion batteries with an operating temperature up to 60 °C.
The demand for high energy Na-ion batteries has promoted intensive research on high energy oxygen redox chemistry in layered transition metal oxide cathodes. However, most layered cathodes with ...oxygen redox might suffer from irreversible electrochemical reaction, fast capacity decay and underlying O2 release. Herein, we report that copper element with a strong electronegativaty can stablize Na-deficient P2-Na2/3Mn0.72Cu0.22Mg0.06O2 phase to achieve both cationic and anionic redox chemistry. Hard and soft X-ray absorption spectra demonstrate that all Mn3+/Mn4+, Cu2+/Cu3+ and O2−/(O2)n− participate in the redox reaction upon Na+ ions extraction and insertion. Density functional theory (DFT) calculations confirm that the strong covalency between copper and oxygen ensures the cationic and anionic redox activity in P2-Na2/3Mn0.72Cu0.22Mg0.06O2 phase. The P2-Na2/3Mn0.72Cu0.22Mg0.06O2 cathode could deliver stable cycling life with 87.9% capacity retention at 1C during 100 cycles, as well as high rate performance (70.3 mA h g−1 cycled at 10C). Our findings not only provide a promising guidelines to enhance the electrochemical performance of layered oxides based on anionic redox activity, but also explore the potential science behind oxygen redox process.
A new Na-deficient P2-Na2/3Mn0.72Cu0.22Mg0.06O2phase that shows both cationic and anionic activity using a strong electronegative copper element. The existence of strong covalency between copper and oxygen promises cationic and anionic redox chemistry upon solid-solution Na+ ions extraction and insertion process. As a result, this phase could deliver stable cycling life in both Na-half cells and full Na-ion cells. Display omitted
•A new Na-deficient P2-Na2/3Mn0.72Cu0.22Mg0.06O2 phase that shows both cationic and anionic activity.•The existence of strong covalency between Cu 3d and O 2p orbitals promises cationic and anionic redox chemistry.•This new Na-deficient P2-Na2/3Mn0.72Cu0.22Mg0.06O2phase could deliver stable cycling life in both half and full Na-ion cells.
The impact of climate change on tourism has always been an important topic for research in the field of international tourism, and haze has been widely recognized as the primary negative factor ...affecting the development of inbound tourism in China. In this study, we first conduct a theoretical analysis of the mechanism through which haze influences the tourism industry, and then we empirically analyze the impact on China's inbound tourism using surface particulate matter (PM2.5) concentrations as a proxy for haze, based on provincial panel data from 1998 to 2016. The empirical results show that haze not only has an inhibitory effect on inbound tourism, but also significantly reduces the average length of stay of international tourists. In addition, while there are significant regional differences in the crowding-out effect of haze pollution on inbound tourism, the effect varies depending on the origin of inbound tourists, exhibiting the greatest negative impact on inbound tourism from Taiwan and the smallest from foreign countries. Our research highlights that haze pollution can led to the change of human tourism behavior which enrich the literature on tourism and haze.
Potassium-ion hybrid capacitors (KIHCs) have attracted growing attention due to the natural abundance and low cost of potassium. However, KIHCs are still limited by sluggish redox reaction kinetics ...in electrodes during the accommodation of large-sized K+. Herein, a starch-derived hierarchically porous nitrogen-doped carbon (SHPNC) anode and active carbon cathode were rationally designed for dual-carbon electrode-based KIHCs with high energy density. The hierarchical structure and rich doped nitrogen in the SHPNC anode result in a distensible interlayer space to buffer volume expansion during K+ insertion/extraction, offers more electrochemical active sites to achieve high specific capacity, and has highly efficient channels for fast ion/electron transports. The in situ Raman and ex situ TEM demonstrated a reversible electrochemical behavior of the SHPNC anode. Thus, the SHPNC anode delivers superior cycling stability and a high reversible capacity (310 mA h g–1 at 50 mA g–1). In particular, the KIHCs assembled by the SHPNC anode and commercial active carbon cathode can deliver a high energy density of 165 W h kg–1 at a current density of 50 mA g–1 and an ultra-long cycle life of 10,000 cycles at 1 A g–1 (calculated based on the total mass of the anode and cathode).
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