Aqueous Rechargeable Sodium-ion Batteries Research Articles

Fully-Printed Flexible Aqueous Rechargeable Sodium-Ion Batteries.

The flexible aqueous rechargeable sodium-ion batteries (ARSIBs) are a promising portable energy storage system that can meet the flexibility and safety requirements of wearable electronic devices. However, it faces huge challenges in mechanical stability and facile manufacturing processes. Herein, the first fully-printed flexible ARSIBs with appealing mechanical performance by screen-printing technique is prepared, which utilizes Na3 V2 (PO4 )2 F3 /C (NVPF/C) as the cathode and 2% nitrogenous carbon-loaded Na3 MnTi(PO4 )3 /C (NMTP/C/NC) as the anode. In particular, the organic co-solvent ethylene glycol (EG) is cleverly added to 17m (molkg-1 ) NaClO4 electrolyte to prepare a 17 m NaClO4 -EG mixed electrolyte. This mixed electrolyte can withstand low temperatures of -20°C in practical applications. Encouragingly, the fully-printed flexible ARSIBs (NMTP/C/NC//NVPF/C) exhibit a discharge capacity of 40.1mAhg-1 , an energy density of 40.1Whkg-1 , and outstanding cycle performance. Moreover, these batteries with various shapes can be used as an energy wristband for an electronic watch in the bending states. The fully-printed flexible ARSIBs in this work are expected to shed light on the development of energy for wearable electronics.

Tuning the Interfacial Chemistry for Stable and High Energy Density Aqueous Sodium-Ion/Sulfur Batteries

The environmental-related issues arising from the fossil fuel assorted industrial revolution and worldwide development have prompted the quest for rechargeable batteries. In these predicaments, lithium-ion batteries (LIBs) took ownership to reshape our lives. However, the limited abundance, non-uniform geographical distribution and severe flammability of organic electrolytes, increase the uncertainty over their large-scale application. Recently, aqueous rechargeable sodium-ion batteries (ARSIBs) have gained considerable curiosity for large-scale energy storage due to their much-assured safety, environment friendliness, high-rate capacity, and low cost. However, the prospects of ARSIBs seeing commercial success remained remote due to the narrow water stability window (1.23 V), which translates into low cell voltage (< 1.6 V), low energy density (< 70 Wh Kg-1), and compromised cycling stability. The aforesaid dilemmas can be resolved by generating a protective layer known as a solid electrolyte interface (SEI) like in organic electrolytes. However, the SEI concept in aqueous electrolytes is relatively unexplored, as water dissociation leads to O2 and H2, and will enhance the parasitic reactions. The SEI formed in WiSE due to salt reduction is often inhomogeneous with a porous mosaic structure and is susceptible to mechanical cracking, and increase the overall cost. Hence, high-capacity electrodes and high voltage electrolytes capable of forming a stable SEI are urgently required to fulfill the dream of the large-scale application of ARSIBs.Recently low cost, highly abundant sulfur-based electrode material has attracted significant research attention due to its high theoretical capacity (1675 mA h g-1) and energy density. However, sluggish sulfur redox kinetics, acute polysulfide shutting, dendritic growth on the metal-based anode and low conductivity of sulfur and its discharge products proves to be a major roadblock for its commercialization. Utilizing abundant sulfur in an aqueous electrolyte along with abundant Na+ can resolve the kinetics and conductivity anxieties and leads to a new greener and safer Na-ion/S batteries chemistry. However lower order polysulfide dissolution in water is more feasible, leading to the rapid capacity decay and active sulfur loss due to H2S formation. Polysulfide dissolution is an interfacial mechanism occurring at the electrode-electrolyte interface and depends on both electrode and electrolyte merits. Therefore, an effective approach will be to couple efficient sulfur host with an electrolyte capable of generating a stable SEI on the electrode surface to prevent the direct attack of water on polysulfide.Herein we have explored urchin-like CoWO4 as a sulfur host coupled with Na-W-U-D electrolyte. The CoWO4 exhibits high conductivity, strong chemical interaction for sulfur and its discharge products, and urchin-like morphology having exposed edges facilitate the charge transport results in excellent polysulfide redox kinetics. The high voltage Na-W-U-D electrolyte was prepared by mixing NaClO4, urea, and N, N-dimethylformamide DMF in 1:2:1 ratio in water. Each component in the electrolyte plays an important role. Urea has very high water solubility and tends to form stable SEI, while DMF has a high dielectric constant, good solvation ability, and develop stabilize SEI. As a result, Na-W-U-D shows a stability window close to the 3.1 V regime due to reduced water activity resulting from complex ion solvent interaction and stable and uniform SEI formation, consisting of Na2CO3, polyurea, and reduction products of DMF. Despite the addition of DMF, non-flammable features of aqueous electrolytes remain well maintained. Herein for the first time, the SEI concept was successfully used for the aq. Na-ion/S battery. We discovered that the lower water activity of Na-W-U-D electrolyte hindered polysulfide dissolution and stable SEI prevent the direct attack of water on polysulfide and results in extended cycling stability. At the same time, the urchin-like CoWO4 host enhances the sluggish polysulfide redox kinetics and provides an abundant anchoring site for polysulfide adsorption. We investigate the effect of time, C-rate, depth of discharge, and dissolved oxygen on polysulfide dissolution and self-discharge of the negative electrode. The high electrode capacity combined with the safety and stable SEI of Na-W-U-D electrolyte translated into a record high initial capacity of 834 mA h g-1 w.r.t sulfur, with remarkable cycling stability up to 500 cycles @ 0.5 C. Post analysis by SEM and XPS, evident that the stable SEI consists of Na2CO3, polyurea, and reduced products of DMF (CO and NHMe2), which also prevent the negative electrode from self-discharge by mitigating the parasitic reaction of dissolved oxygen in the electrolyte. Moreover, a full cell assembled by integrating S@CoWO4 anode and Na0.44MnO2 cathode showed remarkable stability and a high energy density of 119 Wh kg-1, making it a promising candidate for a future energy storage system. Figure 1

Investigation of high-entropy Prussian blue analog as cathode material for aqueous sodium-ion batteries

Aqueous rechargeable sodium-ion batteries (ARSIBs) have received considerable attention as promising alternatives to lithium-ion batteries (LIBs) owing to their safety, environmental friendliness, low cost, and high charge/discharge capacities.

Inlaying Bismuth Nanoparticles on Graphene Nanosheets by Chemical Bond for Ultralong-Lifespan Aqueous Sodium Storage.

Rechargeable aqueous sodium ion batteries (ASIBs) are rising as an important alternative to lithium ion batteries, owing to their safety and low cost. Metal anodes show a high theoretical capacity and nonselective hydrated ion insertion for ASIBs, yet their large volume expansion and sluggish reaction kinetics resulted in poor electrochemical stability. Herein, we demonstrate an electrode cyclability enhancement mechanism by inlaying bismuth (Bi) nanoparticles on graphene nanosheets through chemical bond, which is achieved by a unique laser induced compounding method. This anchored metal-graphene heterostructure can effectively mitigate volume variation, and accelerate the kinetic capability as the active Bi can be exposed to the electrolyte. Our method can achieve a reversible capacity of 122 mAh g-1 at a large current density of 4 A g-1 for over 9500 cycles. This finding offers a desirable structural design of other metal anodes for aqueous energy storage systems.

Aqueous Rechargeable Sodium-Ion Batteries: From Liquid to Hydrogel

Sodium-ion batteries stand out as a promising technology for developing a new generation of energy storage devices because of their apparent advantages in terms of costs and resources. Aqueous electrolytes, which are flame-resistant, inexpensive, and environmentally acceptable, are receiving a lot of attention in light of the present environmental and electronic equipment safety concerns. In recent decades, numerous improvements have been made to the performance of aqueous sodium-ion batteries (ASIBs). One particular development has been the transition from liquid to hydrogel electrolytes, whose durability, flexibility, and leakproof properties are eagerly anticipated in the next generation of flexible wearable electronics. The current review examines the most recent developments in the investigation and development of the electrolytes and associated electrode materials of ASIBs. An overview of new discoveries based on cycle stability, electrochemical performance, and morphology is presented along with previously published data. Additionally, the main milestones, applications, and challenges of this field are briefly discussed.

Promoting the performances of NaTi2(PO4)3@C porous composite as novel anode materials for application in sodium ion battery

Rechargeable aqueous sodium-ion batteries (SIBs) are urgently pursued as a low-cost candidate for grid-scale storage of intermittent renewable energies. NASICON-type NaTi2(PO4)3 holds great promises as anode material for aqueous SIBs owing to the high theoretical capacity and low redox potential, but being severely challenged by poor cycling performance and low reaction kinetics. In this study, a porous carbon-decorated NaTi2(PO4)3 composite was made using a simple sol-gel method and then thermally treated. The NaTi2(PO4)3 particles are adhered to the surface of carbon sheets uniformly. The NTP@C electrode delivers a reversible capacity of 198.1 mAhg−1 at 0.2 C, which is much higher than NTP (125.5 mAhg−1). Atta 50 cycle, a capacity of 196.5 mAhg−1 can be obtained for the NTP@C composite, which in about 99.1% of its initial capacity. From the EIS, RCT value of NTP@C was estimated to be 51.32 Ὠ which is lower than that of bar NTP (78.2 Ὠ). Carbon greatly improves the cell's performance, particularly the cycle lifetime at high charge-discharge rates of NTP electrodes. The increased structural stability and electron/Na + ion transfer kinetics of the NTP@C anode material are responsible for its exceptional electrochemical properties and long cycle lifespan.

Newly developed γ-NaTiOPO4 by simple solid-state synthesis for anode material of Na-ion batteries in both nonaqueous and aqueous electrolytes

Sodium-ion batteries (SIBs) are a promising next-generation energy storage system in terms of cost due to the abundance of sodium. However, obtaining good anode materials for SIBs remains a challenge. NaTiOPO4 has been investigated as an anode not only for SIBs but also for aqueous SIBs. Despite the various NaTiOPO4 polymorphs, only the β-NaTiOPO4 phase has been investigated as an anode for SIBs due to the limited synthesis process. In this study, we successfully stabilized γ-NaTiOPO4 via our newly developed solid-state synthesis process. In addition, its electrochemical properties as an anode for SIBs were investigated in this study. The synthesized material demonstrates a high voltage of 1.7 and ∼1.5 V vs Na/Na+ with 120 mAh/g and good capacity retention of 64% for up to 500 cycles at 0.5C in a nonaqueous electrolyte. In an aqueous electrolyte, Na0·44MnO2//γ-NaTiOPO4 full cell achieves excellent stable capacity retention with a high Coulombic efficiency for 175 cycles. It shows high cycling stability with a three-dimensional framework despite the relatively high redox potential. Thus, it demonstrates that γ-NaTiOPO4 is a promising anode material for both nonaqueous and aqueous rechargeable SIBs.

Transparent aqueous rechargeable sodium-ion battery

Aqueous sodium-ion battery is a sustainable, non-toxic, non-flammable, and low-cost alternative to lithium-ion batteries, while transparency is a growing requisite of modern and integrated devices that batteries have yet to fulfill. In this work we present the preparation of a transparent and rechargeable aqueous Na-ion battery, assembled with different thin films of carbon/cobalt-based nanomaterials as electrodes. Cobalt-filled carbon nanotubes and cobalt/cobalt oxide encapsulated carbon nanoparticles are simultaneously synthesized in one single experimental procedure and deposited as thin and transparent films through the liquid/liquid interfacial route. The former is used for the electrosynthesis of a Prussian blue analogue, yielding carbon nanotubes/cobalt hexacyanoferrate thin film nanocomposite used as cathodes, while the cobalt/cobalt oxide/carbon nanoparticles thin film is used as the anode. The transparent device is prepared using a diluted aqueous solution of NaCl as the electrolyte, reaching capacities of 22 mAh•g−1 at 2 A•g−1 that remains stable after 2000 charge/discharge cycles, and energy density of 19.2 Wh•kg−1 at 1.4 kW•kg−1.

Electrochemical Study of NaFePO4 Cathode Material in Aqueous Sodium-ion Electrolyte

Aqueous rechargeable sodium-ion batteries (ARSIBs) have received more attention because of their low cost, the vast abundance of sodium on the earth, and possible application for smart grid-scale energy storage systems. This work reports the synthesis of NaFePO4 by a low-temperature ionothermal method using deep eutectic solvent (DES). The physical characterization of the synthesized material is done using X-Ray Diffraction (XRD), Scanning electron microscopy (SEM), Energy Dispersive X-ray analysis (EDAX), thermogravimetry analysis (TGA), and differential scanning calorimetry (DSC) to evaluate its crystal size, structure, composition, and morphology. The electrochemical behavior of NaFePO4 in 5M NaNO3 is studied using cyclic voltammetry (CV) and galvanostatic charge-discharge techniques. The electrochemical study revealed that the synthesized cathode material, NaFePO4 exhibits excellent electrochemical performance at high current rates. The full cell NaTi2(PO4)3/5M NaNO3/NaFePO4 delivers a discharge capacity of 96.96 mAh g-1at C/5rate and is 62.96% of the theoretical capacity. The cell retains a discharge capacity of 76 mAh g-1 over 50 cycles with good rate capability.

Towards High‐Performance Aqueous Sodium Ion Batteries: Constructing Hollow NaTi2(PO4)3@C Nanocube Anode with Zn Metal‐Induced Pre‐Sodiation and Deep Eutectic Electrolyte

AbstractThe aqueous rechargeable sodium‐ion battery (ARSIB) is considered to be the most promising candidate for large‐scale energy storage applications, due to its low cost, safety, and eco‐friendliness. However, the poor cycle life and low energy density of ARSIB impede its practical applications. In this context, hollow NaTi2(PO4)3 nanocubes anode is engineered through a facile, low‐cost, and large‐scale hydrothermal approach. Na0.44MnO2 cathode delivers a high capacity of 75.16 mAh g−1 with the compensation of sodium ions by the zinc metal‐induced pre‐sodiation of the anode in a deep eutectic electrolyte. The well‐designed structure in hollow carbon‐coated NaTi2(PO4)3 nanocubes enables high stability and rate performance. Moreover, the adoption of deep eutectic electrolytes can minimize the Mn dissolution in the Na0.44MnO2 cathode. When coupling the cathode and anode, the as‐assembled ARSIB with a deep eutectic electrolyte exhibits an ultralong cycle life up to 3500 cycles (with capacity retention of 90%), an ultrahigh energy density of 50.0 Wh kg−1, and superior rate capability (maximum power density of 1500 W kg−1). This ARSIB represents an alternative promising candidate for large‐scale electrochemical energy storage.

A binder-free δ-MnO2@reduced graphene oxide composite film as a bi-functional electrode for aqueous rechargeable sodium-ion batteries and hybrid capacitive deionization

The freestanding δ-MnO2@rGO/CC electrode exhibits stable operation performance for both ASIBs and HCDI.

Graphene Modified Vanadium Oxide Composite Materials Used in Aqueous Na-Ion Batteries

Divanadium pentoxide as an electrode material in the aqueous-based battery has been widely explored because of its higher theoretical capacity and potential crystal structure. Here, in this work, we present vanadium pentoxide modified with graphene (V2O5@G) as an anode material in an aqueous rechargeable sodium-ion battery (ARSB) prepared via a facile one-step hydrothermal method followed by annealing. The complete ARSB was assembled by employing Na0.44MnO2 as the cathode material, which was synthesized via the sol–gel method. The assembled ARSBs were subjected to cyclic voltammetry, charge–discharge, and rate performance; it has been suggested that incorporation of graphene has a positive effect on the overall battery performance observed through charge–discharge (38.2 mAh g–1), cyclic capacity retention (200 cycles at 1A g–1 with a retention rate of 53%), and rate performance in contrast with pristine vanadium pentoxide. Further investigation suggested V2O5@G had larger sodium storage capacity, improved rate capability, increased Na+ diffusivity, and reduced electrochemical reaction resistance.

Synthesis of Flower-Like, Hyperbranched Na3FePO4CO3 Nanocrystals and Their Electrochemical Performance as Cathodes in Aqueous Rechargeable Sodium-Ion Batteries

Aqueous rechargeable sodium-ion batteries (ARSBs) have received much attention due to their low cost, the vast abundance of sodium, and the possible application for a smart grid-scale energy storage system. Here, we synthesized Na3FePO4CO3, a cathode material for ARSBs by a low-temperature ionothermal method using deep eutectic solvent and investigated its electrochemical performance. The physical characterization of the synthesized cathode material was done using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, thermogravimetry analysis, differential thermal analysis, and X-ray photoelectron spectroscopy to evaluate crystal size, structure, elemental composition, morphology, and oxidation state. The electrochemical behavior of Na3FePO4CO3 in 2 M Na2SO4 was studied using cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge techniques. The study revealed that at high current rates, the synthesized cathode material, Na3FePO4CO3 exhibited excellent electrochemical performance. The full cell NaTi2(PO4)3/2 M Na2SO4/Na3FePO4CO3 delivers a discharge capacity of 78.6 mAh g−1 at C/5 rate which is 82% of the theoretical capacity (96 mAh g−1 for one-electron reaction) and 41.62 mAh g−1 at 2 C rate Further, it retains a discharge capacity of 70 mAh g−1 over 100 cycles with good cyclability.

Corrigendum to “NaTi2(PO4)3 hollow nanoparticles encapsulated in carbon nanofibers as novel anodes for flexible aqueous rechargeable sodium-ion batteries” [Nano Energy 82 (2021) 105764

Corrigendum to “NaTi2(PO4)3 hollow nanoparticles encapsulated in carbon nanofibers as novel anodes for flexible aqueous rechargeable sodium-ion batteries” [Nano Energy 82 (2021) 105764

NaTi2(PO4)3 hollow nanoparticles encapsulated in carbon nanofibers as novel anodes for flexible aqueous rechargeable sodium-ion batteries

NASICON‐structured NaTi 2 (PO 4 ) 3 (NTP) is an attractive anode material for aqueous rechargeable sodium-ion batteries (ARSIBs) thanks to its three-dimensional open framework and appropriate negative voltage window. Nevertheless, the lack of flexible and high-performance binder-free NTP-based anodes remains stumbling blocks to the development of wearable ARSIBs. Herein, hollow-structure NTP evenly encapsulated in cross-linked porous N-doped carbon nanofiber (HNTP@PNC) is prepared through electrospinning technology and subsequent carbonization treatment, directly acting as binder-free anode for flexible ARSIBs. Benefiting from its unique hollow structure, continuous conductive network and favorable synergistic effect, the HNTP@PNC electrode displays as high as of 108.3 mAh g −1 rate capacity at 5.50 A g −1 and an impressive cycling stability of 97.2% capacity retention after 3000 cycles. Further, theoretical calculations reveal that NTP with NC coating significantly enhances electronic conductivity and accelerates Na + diffusion kinetics. Pairing with potassium zinc hexacyanoferrate free-standing cathode, a prototype quasi-solid-state ARSIB with a high-voltage discharge plateau of 1.6 V is successfully constructed, achieving a high volumetric capacity of 24.5 mAh cm −3 and an admirable energy density of 39.2 mWh cm −3 , outperforming most reported flexible aqueous rechargeable energy-storage devices. These exciting results provide valuable intuition into the design of novel binder-free NTP-based anodes for next-generation wearable ARSIBs. • A facial template-free solvothermal method was developed to synthesize the rugby-like NTP nanoparticles with well-defined hollow structures. • By combining with an electrospinning technique and subsequent carbonization treatment, HNTP@PNC was prepared and firstly served as the binder-free anode for flexible ARSIBs. • A quasi-solid-state ARSIB achieves high volumetric capacity (24.5 mAh cm −3 ) and admirable energy density (39.2 mWh cm −3 ).

High-capacity and cycling-stable polypyrrole-coated MWCNT@polyimide core-shell nanowire anode for aqueous rechargeable sodium-ion battery

Aqueous rechargeable sodium-ion batteries (ARSBs) have potential applications in large-scale electric energy storage systems because of the non-flammable and fast charge-discharge performance of the aqueous neutral electrolyte as well as low cost and abundance of sodium resources. Herein, we demonstrate polypyrrole-coated MWCNT@polyimide core-shell nanowire based on pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (ODA) as a high-capacity and cycling-stable anode material for ARSBs. The as-synthesized MWCNT@polyimide core-shell nanowire exhibits excellent initial discharge capacity as high as 234.9 mA h g −1 , which is 83.6% of the theoretical value, owing to the bicontinuous electron/ion transport pathway. During 100 cycles of charge-discharge, however, the considerable swelling of PMDA-ODA polyimide and structural degradation of core-shell structure result in significant deterioration in the performance from 234.9 to 74.6 mAh g −1 . In order to improve the cycling stability, conducting polypyrrole is coated on its surface. After 100 charge-discharge cycles, the polypyrrole-coated MWCNT@polyimide core-shell nanowire retains a specific capacity of 209.3 mA h g −1 , corresponding to 77.8% of the initial capacity, without any swelling and structural degradation. In impedance study, the changes in the surface and charge transfer resistances during charge-discharge cycles are significantly reduced. As a result, the polypyrrole layer successfully inhibits the structural degradation of the MWCNT@polyimide core-shell nanowire, and consequently improves the cycling performance. • MWCNT@polyimide nanowire is used as an anode for aqueous sodium-ion battery. • Commercially available PMDA-ODA polyimide is used as active material. • The specific capacity is 209.3 mA h g −1 after 100 cycles at 280 mA g −1 (1C). • Polypyrrole layer on polyimide inhibits the degradation of PMDA-ODA polyimide.

Studies on micron-sized Na0.7MnO2.05 with excellent cycling performance as a cathode material for aqueous rechargeable sodium-ion batteries

Aqueous rechargeable sodium-ion batteries (ARSB) have great potential as large-scale storage devices owing to their low cost, high energy density, safety, and environmental friendliness. Here, micron-sized Na0.7MnO2.05, fabricated by a facile sol–gel method, is reported as a novel cathode material for ARSB and has been characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), selected area electron diffraction/energy dispersive spectroscopy (ED/EDS) and X-ray photoelectron spectroscopy (XPS). As revealed, the material is perfectly synthesized. The Na0.7MnO2.05 electrode delivers an initial charge specific capacity of 42.6 mA h g−1 at a current density of 50 mA g−1. Compared with the capacity of 100th cycle (the highest discharge specific capacity of 52 mA h g−1), a capacity retention of 90.1% after 600 cycles is still observed. Good rate performance and excellent long-term cycling capability are also demonstrated. Unique morphology, medium-sized and mono-disperse particles facilitate the diffusion of Na+ in the electrode, which is also beneficial for Na0.7MnO2.05 electrode to exhibit excellent electrochemical performance.

Insight into Electrochemical Properties and Reaction Mechanism of a Cobalt-Rich Prussian Blue Analogue Cathode in a NaSO3CF3 Electrolyte for Aqueous Sodium-Ion Batteries

Prussian-blue analogues attract significant interest as cathode materials for rechargeable aqueous sodium-ion batteries (SIBs) owing to their open-framework structure and good cycling stability in ...

Conversion Synthesis of Self-Standing Potassium Zinc Hexacyanoferrate Arrays as Cathodes for High-Voltage Flexible Aqueous Rechargeable Sodium-Ion Batteries.

Prussian blue analogs exhibit great promise for applications in aqueous rechargeable sodium-ion batteries (ARSIBs) due to their unique open framework and well-defined discharge voltage plateau. However, traditional coprecipitation methods cannot prepare self-standing electrodes to meet the needs of wearable energy storage devices. In this work, a water bath method is reported to grow microcube-like K2 Zn3 (Fe(CN)6 )2 ·9H2 O on carbon cloth (CC) using Zn nanosheet arrays as the zinc source and reducing agent, directly serving as a self-standing cathode. Benefiting from fast ion diffusion and high conductivity, the cathode delivers a high areal capacity of 0.76 mAh cm-2 at 0.5 mA cm-2 and excellent capacity retention of 57.9% as the current density increases to 20 mA cm-2 . By coupling with NaTi2 (PO4 )3 grown on CC as an anode, a quasi-solid-state flexible ARSIB with a high output voltage plateau of 1.6 V is successfully assembled, exhibiting a superior areal capacity of 0.56 mAh cm-2 and energy density of 0.92 mWh cm-2 . In particular, the device shows admirable mechanical flexibility, maintaining 90.3% of initial capacity after 3000 bending cycles. This work is anticipated to open a new avenue for the rational design of self-standing electrodes used in high-voltage flexible ARSIBs.

All Binder-Free Electrodes for High-Performance Wearable Aqueous Rechargeable Sodium-Ion Batteries

HighlightsNanocube-like KNiFe(CN)6 and rugby ball-like NaTi2(PO4)3 are grown on carbon nanotube fibers via simple and mild methods.A quasi-solid-state fiber-shaped aqueous rechargeable sodium-ion battery based on all binder-free electrodes is successfully assembled for the first time, delivering a high volumetric capacity of 34.21 mAh cm−3 and impressive volumetric energy density of 39.32 mWh cm−3.The device delivers superior mechanical flexibility with only 5.7% of initial capacity loss after bending at 90° for over 3000 cycles.