Aqueous zinc-ion batteries (ZIBs) has been regarded as a promising energy storage system for large-scale application due to the advantages of low cost and high safety. However, the growth of Zn ...dendrite, hydrogen evolution and passivation issues induce the poor electrochemical performance of ZIBs. Herein, a Na3Zr2Si2PO12 (NZSP) protection layer with high ionic conductivity of 2.94 mS/cm on Zn metal anode was fabricated by drop casting approach. The protection layer prevents Zn dendrites formation, hydrogen evolution as well as passivation, and facilitates a fast Zn2+ transport. As a result, the symmetric cells based on NZSP-coated Zn show a stable cycling over 1360 h at 0.5 mA/cm2 with 0.5 mAh/cm2 and 1000 h even at a high current density of 5 mA/cm2 with 2 mAh/cm2. Moreover, the full cells combined with V2O5-based cathode displays high capacities and high rate capability. This work offers a facile and effective approach to stabilizing Zn metal anode for enhanced ZIBs.
Na3Zr2Si2PO12 (NZSP) protection layer with high ionic conductivity on Zn metal prevents side reactions, hydrogen evolution as well as dendrite formation, which endows improved electrochemical performance of symmetric cells and full cells. Display omitted
Aqueous zinc-ion batteries (ZIBs) with the characteristics of low production costs and good safety have been regarded as ideal candidates for large-scale energy storage applications. However, the ...nonconductive and non-redox active polymer used as the binder in the traditional preparation of electrodes hinders the exposure of active sites and limits the diffusion of ions, compromising the energy density of the electrode in ZIBs. Herein, we fabricated vanadium pentoxide nanofibers/carbon nanotubes (V
O
/CNTs) hybrid films as binder-free cathodes for ZIBs. High ionic conductivity and electronic conductivity were enabled in the V
O
/CNTs film due to the porous structure of the film and the introduction of carbon nanotubes with high electronic conductivity. As a result, the batteries based on the V
O
/CNTs film exhibited a higher capacity of 390 mAh g
at 1 A g
, as compared to batteries based on V
O
(263 mAh g
). Even at 5 A g
, the battery based on the V
O
/CNTs film maintained a capacity of 250 mAh g
after 2000 cycles with a capacity retention of 94%. In addition, the V
O
/CNTs film electrode also showed a high energy/power density (e.g., 67 kW kg
/267 Wh kg
). The capacitance response and rapid diffusion coefficient of Zn
(~10
cm
s
) can explain the excellent rate capability of V
O
/CNTs. The vanadium pentoxide nanofibers/carbon nanotubes hybrid film as binder-free cathodes showed a high capability and a stable cyclability, demonstrating that it is highly promising for large-scale energy storage applications.
The development of reliable and affordable all‐solid‐state sodium metal batteries (ASS‐SMBs) requires suitable solid‐state electrolytes with cost‐efficient processing and stabilized ...electrode/electrolyte interfaces. Here, an integrated porous/dense/porous Na5YSi4O12 (NYS) trilayered scaffold is designed and fabricated by tape casting using aqueous slurries. In this template‐based NYS scaffold, the dense layer in the middle serves as a separator and the porous layers on both sides accommodate the active materials with their volume changes during the charge/discharge processes, increasing the contact area and thus enhancing the utilization rate and homogenizing the current distribution. The Na/NYS/Na symmetric cells with the Pb‐coated NYS scaffold exhibit significantly reduced interfacial impedance and superior critical current density of up to 3.0 mA cm−2 against Na metal owing to enhanced wettability. Furthermore, the assembled Na/NYS/S full cells operated without external pressure at room temperature showed a high initial discharge capacity of 970 mAh g−1 and good cycling stability with a capacity of 600 mAh g−1 after 150 cycles (based on the mass of sulfur). This approach paves the way for the realization of economical and practical ASS‐SMBs from the perspective of ceramic manufacturing.
The porous/dense/porous trilayered Na5YSi4O12 is used in an all‐solid‐state sodium/sulfur battery as a scaffold for the electrode active materials. The dense middle layer separates both electrodes and prevents sulfur shuttling and sodium dendrite growth. The porous layers on both sides accommodate the active materials and mitigate volume changes, thus increasing the contact area and distributing the local current.
Developing cost-effective and reliable solid-state sodium batteries with superior performance is crucial for stationary energy storage. A key component in facilitating their application is a ...solid-state electrolyte with high conductivity and stability. Herein, we employed aliovalent cation substitution to enhance ionic conductivity while preserving the crystal structure. Optimized substitution of Y3+ with Zr4+ in Na5YSi4O12 introduced Na+ ion vacancies, resulting in high bulk and total conductivities of up to 6.5 and 3.3 mS cm−1, respectively, at room temperature with the composition Na4.92Y0.92Zr0.08Si4O12 (NYZS). NYZS shows exceptional electrochemical stability (up to 10 V vs. Na+/Na), favorable interfacial compatibility with Na, and an excellent critical current density of 2.4 mA cm−2. The enhanced conductivity of Na+ ions in NYZS was elucidated using solid-state nuclear magnetic resonance techniques and theoretical simulations, revealing two migration routes facilitated by the synergistic effect of increased Na+ ion vacancies and improved chemical environment due to Zr4+ substitution. NYZS extends the list of suitable solid-state electrolytes and enables the facile synthesis of stable, low-cost Na+ ion silicate electrolytes.
Potassium-ion capacitors (PICs), skillfully combining the features of batteries and capacitors, hold promise in energy conversion and storage. Cobalt sulfide (CoS2) anode are promising alternatives ...due to its high theoretical capacity and excellent potassium storage capacity. However, severe volume changes of CoS2 anode leads to capacity decline and poor cycle stability, hindering its application in PICs. Herein, we successfully confine CoS2 nanoparticles in N-doped coal-based carbon fibers (CoS2/CF). Coal-based carbon fibers with flexible characteristic elevate the conductivity and relieve the volume expansion of CoS2. Moreover, the high content of edge nitrogen as active sites further enhances the electrochemical properties. The PICs with flexible CoS2/CF-0.8 as anode exhibits superior specific capacity (331.1mAh g-1 after 150 cycles at 0.1Ag-1) and long cycling (214.1mAh g-1 after 900 cycles at 1.0Ag-1). Ex-situ X-ray powder diffraction (XRD) reveal that the mechanism of CoS2/CF-0.8 anode is based on reversible intercalation and conversion reaction. Importantly, CoS2/CF-0.8||activated carbon (AC) devices shows excellent energy density (101.9Wh kg-1) and long cycling (82.23% capacity maintenance rate after 1000 cycles). This work offers insights for other materials with high theoretical capacity but volume expansion problem.
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•Self-supporting CoS2/N-doped carbon nanofibres (CoS2/CF) composite were designed and constructed successfully.•The combination of the 1D structure and N-doped strategy enhance the conductivity and relieve the volume expansion of CoS2/CF.•CoS2/CF||AC potassium ion capacitors displays high energy/power density and capacity retention.
Quinone-based sodium-ion batteries (SIBs) are highly desirable electrochemical devices with high capacity and low cost but suffer from poor cycle life and low practical energy because of quinone ...dissolution in aprotic electrolyte. Herein, we report a facile strategy of using ionic liquid (IL) to tackle the dissolution of quinone electrodes. The inhibitory effect of ILs on quinone dissolution correlates with their polarity, donor number, and interaction energy, as revealed by combined density functional theory and spectroscopy studies. Particularly, in N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)amide (PY13TFSI) electrolyte with weak donor ability and large polarity, calix4quinone cathode exhibits high capacity (>400 mAh g−1) and superior capacity retention (∼99.7% at 130 mA g−1 for 300 cycles), significantly outperforming that in ether-based electrolyte. Moreover, the remarkable cyclability and considerable rate capability of 5,7,12,14-pentacenetetrone in PY13TFSI render it a promising sodium-storage material. This work would promote the development of high-performance SIBs with quinone electrodes and IL electrolyte.
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•A facile strategy is proposed to suppress the dissolution of quinone electrodes•Inhibitory effect of ILs correlates to polarity, donor number, and binding energy•PY13TFSI markedly inhibits quinone dissolution•C4Q and PT cathodes exhibit better capacity retention in ILs than in ether
Building advanced sodium-ion batteries with sustainable materials has increasing importance for electrochemical energy storage applications. Organic-based electrode materials are attractive because of their high capacity, resource abundance, environmental benignancy, and low cost. More importantly, the structural diversity and design flexibility of organic materials make them the most promising alternative to inorganic electrode materials built with transition-metal elements. However, organic electrode materials suffer from intrinsically high solubility in aprotic electrolyte, which results in rapid capacity fading and low energy output. Here, we report a facile and general strategy of using ionic liquids to tackle the dissolution problem of organic quinone electrodes. Remarkably, quinone cathodes such as calix4quinone and 5,7,12,14-pentacenetetrone deliver significantly higher sodium-storage capacity and better cyclability in PY13TFSI than in conventional ether electrolyte.
Coupling quinone cathode with ionic liquid electrolyte is demonstrated to build high-energy and long-life sodium-ion batteries. Computational and spectroscopic studies reveal that the inhibitory effect of ionic liquid on dissolution of quinone correlates with the strong polarity, weak electron donor ability, and low interaction energy. The calix4quinone and 5,7,12,14-pentacenetetrone cathodes exhibit significantly improved cycling performance in N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)amide than in ether electrolyte. These results would enlighten the design and application of ionic liquid and quinones for organic batteries.
Potassium (K) metal is considered one of the most promising anodes for potassium metal batteries (PMBs) because of its abundant and low-cost advantages but suffers from serious dendritic growth and ...parasitic reactions, resulting in poor cyclability, low Coulombic efficiency (CE), and safety concerns. In this work, we report a localized high-concentration electrolyte (LHCE) consisting of potassium bis(fluorosulfonyl)imide (KFSI) in a cosolvent of 1,2-dimethoxyethane (DME) and 1,1,2,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) to solve the problems of PMBs. TTE as a diluent not only endows LHCE with advantages of low viscosity, good wettability, and improved conductivity but also solves the dendrite problem pertaining to K metal anodes. Using the formulation of LHCE, a CE of 98% during 800 cycles in the K||Cu cell and extremely stable cycling of over 2000 h in the K||K symmetric cell are achieved at a current density of 0.1 mA cm–2. In addition, the LHCE shows good compatibility with a Prussian Blue cathode, allowing almost 99% CE for the K||KFeIIFeIII(CN)6 full cell during 100 cycles. This promising electrolyte design realizes high-safety and energy-dense PMBs.
•A C@PP separator is proposed to suppress the shuttle of quinone electrodes.•Inhibitory shuttle correlates with the physical barrier and excellent adsorption.•The separator increases the utilization ...of PT cathode for high capacities.•The other three quinone cathodes also exhibit greatly improved performances.
A major challenge facing organic rechargeable batteries is the problem of the dissolution and shuttle effect of organic cathodes in aprotic electrolytes, resulting in limited capacity, low cyclability and poor rate performance. Herein, a functional polypropylene separator coated with Ketjen black (C@PP) was introduced to tackle the shuttle issue. The inhibitory effect on quinone shuttle correlates with physical barrier and excellent adsorption of Ketjen black (KB), as proved by a series of spectroscopy studies. With the C@PP separator, quinone cathodes including pentacene-5,7,12,14-tetrone (PT), Calix4 quinone (C4Q), 9,10-anthraquinone (AQ) and 9,10-phenanthrenequinone (PQ) demonstrated high reversible capacity and excellent cyclic stability in Li storage. Specially, PT exhibited high capacity (>300 mAh g−1), long-term cyclability (~0.06% decay per cycle over 400 cycles at 0.5 C) and fast kinetic (5 C). C4Q delivered high energy density (782 Wh kg−1) and respectable cyclability (~60% after 500 cycles). This facile and versatile separator modifying strategy opens a new avenue for solving quinone electrode issues to achieve high-performance OLBs.
Solid‐state sodium batteries (SSNBs) have attracted extensive interest due to their high safety on the cell level, abundant material resources, and low cost. One of the major challenges in the ...development of SSNBs is the suppression of sodium dendrites during electrochemical cycling. The solid electrolyte Na3.4Zr2Si2.4P0.6O12 (NZSP) exhibits one of the best dendrite tolerances of all reported solid electrolytes (SEs), while it also shows interesting dendrite growth along the surface of NZSP rather than through the ceramic. Operando investigations and in situ scanning electron microscopy microelectrode experiments are conducted to reveal the Na plating mechanism. By blocking the surface from atmosphere access with a sodium‐salt coating, surface‐dendrite formation is prevented. The dendrite tolerance of Na | NZSP | Na symmetric cells is then increased to a critical current density (CCD) of 14 mA cm−2 and galvanostatic cycling of 1 mA cm−2 and 1 mAh cm−2 (half cycle) is demonstrated for more than 1000 h. Even if the current density is increased to 3 mA cm−2 or 5 mA cm−2, symmetric cells can still be operated for 180 h or 12 h, respectively.
Fast Na‐dendrite growth along the surface of Na3.4Zr2Si2.4P0.6O12 (NZSP) rather than through the ceramic is observed. Atmosphere and surface‐coating influence the surface‐dendrite growth on NZSP. After coating the NZSP surface with a protective layer, the critical current density of the Na | NZSP | Na symmetric cells increases up to 14 mA cm−2. The cell withstands galvanostatic cycling with 1 mA cm−2 and 1 mAh cm−2 for 1000 h.
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•Sheets of Na5YSi4O12 Na+ ion superionic conductor were fabricated for the first time.•RT conductivity of Na5YSi4O12 tape has reached 1 mS cm−1.•The electrochemical stability window ...is up to 8 V vs. Na+/Na.•The CCD can reach 2.2 mA cm−2 and galvanostatic cycling is > 280 h under 0.8 mA cm−2.•The aqueous based method is both cost-efficient and eco-friendly.
All-solid-state sodium batteries (ASSNBs), which combine the benefits of high safety and low cost, are expected to be an alternative or complementary storage technology to lithium ion batteries. Herein, we developed an aqueous tape casting technique for the continuous fabrication of ceramic sheets made of silicate-based Na5YSi4O12 (NYS) Na+ ion superionic conductor for the first time. After sintering, the ceramics showed a total conductivity of 1.0 mS cm−1 at room-temperature, low total activation energy of 0.30 eV, and wide electrochemical window of over 8 V. The critical current density of NYS tape against Na-metal electrodes can reach 2.2 mA cm−2 and the galvanostatic cycling time is over 280 h under 0.8 mA cm−2 and 0.8 mAh cm−2. The obtained tape has high crystalline purity, dense microstructure, favorable mechanical properties (hardness H of 2 GPa and elastic modulus E of 45 GPa). This work not only highlights the potential of the scarcely studied silicate-based NYS ionic conductor as a functional separator, but also presents a cost-efficient and eco-friendly continuous fabrication using the aqueous tape casting technique, thus being expected to boost the practical application of NYS as solid-state electrolyte in ASSNBs.
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