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Sodium-ion batteries (SIBs) are promising alternatives to lithium-ion batteries (LIBs) for large-scale energy storage considering the abundance and low cost of Na-containing resources. However, the energy density of SIBs has been limited by the typically low specific capacities of traditional intercalation-based cathodes. Metal fluorides, in contrast, can deliver much higher capacities based on multi-electron conversion reactions. Among metal fluorides, CuF2 presents a theoretical specific capacity as high as 528 mAh/g while its Na-ion storage mechanism has been rarely reported. Here, we report CuF2 as a SIB cathode, which delivers a high capacity of 502 mAh/g but suffers from poor electrochemical reversibility. As a solution, we adjust the cell configuration by inserting a carbon-coated separator, which hinders the transportation of dissolved Cu ions and improves the reversibility of the CuF2 cathode. By using in-situ XRD measurements and theoretical calculation, we propose that a one-step conversion reaction occurs during the discharge process, and a reconversion reaction competes with the oxidization of Cu to dissolved Cu ion during the charge process.

P2-type Na2/3Ni1/3Mn2/3O2 (P2-NaNM) is a promising cathode material for practical applications in Na-ion batteries due to its high capacity. However, the rearrangement of Na+/vacancy order and cathodic charge order across the Na extraction/intercalation and structural rearrangements of P2-NaNM at high voltages result in rapid capacity fading and insufficient rate capability. Here, a combined structural modulation strategy was presented to solve these challenges via reducing the Na layers spacing through substituting Na sites by Mg ions while simultaneously stabilizing the transition metal (TM) layers through Mg/Ti co-doping. Benefited from the symbiotic effect, P2-NaNM exhibits a significantly enhanced cycling stability and rate capability in the voltage range of 3.0–4.4 ​V. We further revealed that Mn remains Mn4+ while Ni2+ becomes Ni3+ at the surface of Mg/Ti co-substituted P2-NaNM upon charge/discharge process.

Na3V2(PO4)2O2F (NVPOF) is considered as a promising cathode material for sodium-ion batteries due to its high structural stability and high average operating voltage (3.8 V). However, its low elect...

The hazard of hexavalent chromium (Cr(VI)) from environmental pollution and medical implanted metal has been recognized widely. However, removal of trace amount of Cr(VI) in the blood circumstance faces tremendous difficulties for that most of Cr(VI) located in erythrocytes, thus there is almost no literature to report the removal of Cr(VI) in blood. Herein, a removal strategy, named as reduction-adsorption-separation, is proposed to realize the removal of Cr(VI) in blood. First, magnetic core-shell mesoporous nanocomposite is fabricated by using Fe3O4 nanoparticles as magnetic core and mesoporous silica (MS) as shell, hyperbranched polyamide (HPA) as mesoporous channel modifier and ascorbic acid (ASC) as the reductant drug loaded in the mesoporous channels, which is also denoted as Fe/MS/HPA/ASC. Then, on the basis of the bionic idea, the erythrocyte membrane (EM)-wrapped Fe/MS/HPA/ASC to protect ASC from deactivation is obtained and named as the therapeutic agent (Fe/MS/HPA/ASC@EM). During removal process, the therapeutic agent can enter in erythrocytes to use ASC to reduce Cr(VI) to Cr(III) and HPA in mesoporous channels to adsorb Cr(III) and can then be recollected from blood by magnetic separation. Finally, an animal model of blood Cr(VI) poisoning is constructed and used to test the removal ability of Cr(VI) from pig blood in vivo, verifying the effectiveness of this blood Cr(VI) removal strategy, providing a possible way to design more efficient and biosafe therapeutic agents for blood purification.

Na2Zn2TeO6 is a potential sodium solid electrolyte of all-solid-state sodium-ion batteries. In this work, Na+ ion conductivity and electrochemical performance of layered Ca-doped Na2Zn2-xCaxTeO6 (x = 0–0.05) (NZTO-Cx) electrolytes have been investigated. The highest conductivity has been achieved 7.54 × 10−4 S cm−1 in NZTO-Cx at x = 0.02, at room temperature due to grain-boundary modification and interlayer-interface elimination. Meanwhile, chemical stability with metallic Na anode and electrochemical window of NZTO-Cx are improved by Ca doping. Furthermore, the cycle stability of Na3V2(PO4)3/NZTO-Cx/Na solid-state batteries have been successfully increased by Ca doping. These advantages highly demonstrate good potential application prospect of NZTO-Cx in all-solid-state sodium-ion batteries.

Low-cost layered oxides free of Ni and Co are considered to be the most promising cathode materials for future sodium-ion batteries. Biphasic Na0.78 Cu0.27 Zn0.06 Mn0.67 O2 obtained via superficial atomic-scale P3 intergrowth with P2 phase induced by Zn doping, consisting of inexpensive transition metals, is a promising cathode for sodium-ion batteries. The P3 phase as a covering layer in this composite shows not only in excellent electrochemical performance but also its tolerance to moisture. The results indicate that partial Zn substitutes can effectively control biphase formation for improving the structural/electrochemical stability as well as the ionic diffusion coefficient. Based on in situ synchrotron X-ray diffraction coupled with electron-energy-loss spectroscopy, a possible Cu2+/3+ redox reaction mechanism has now been revealed.

We are presenting a sol–gel method for building novel nanostructures made of nanosized F-doped Na1–2xTi2(PO4)3–xFx (NTP-Fx, x = 0, 0.02, 0.05, and 0.10) particles embedded in three-dimensional (3D)...

Structural degradation in manganese oxides leads to unstable electrocatalytic activity during long-term cycles. Herein, we overcome this obstacle by using proton exchange on well-defined layered Li2MnO3 with an O3-type structure to construct protonated Li2-xHxMnO3-n with a P3-type structure. The protonated catalyst exhibits high oxygen reduction reaction activity and excellent stability compared to previously reported cost-effective Mn-based oxides. Configuration interaction and density functional theory calculations indicate that Li2-xHxMnO3-n has fewer unstable O 2p holes with a Mn3.7+ valence state and a reduced interlayer distance, originating from the replacement of Li by H. The former is responsible for the structural stability, while the latter is responsible for the high transport property favorable for boosting activity. The optimization of both charge states to reduce unstable O 2p holes and crystalline structure to reduce the reaction pathway is an effective strategy for the rational design of electrocatalysts, with a likely extension to a broad variety of layered alkali-containing metal oxides., Structural degradation in manganese oxides leads to unstable activity during long-term cycles. Herein, authors demonstrated that reduced unstable O 2p holes and the short interlayer distance of layered lithium manganese oxide are favorable for excellent electrocatalytic stability and activity.

The development of sodium-ion batteries (SIBs) remains a great challenge due to poor stability and sluggish kinetics of cathode materials. Here, we present Ti-substituted Na3-xV2-xTix(PO4)3/C (NVP-Tix/C，0 ≤ x ≤ 0.2) as high-performance cathode materials for SIBs. Crystal structure and Na storage properties are investigated by experiment and theoretical calculation. X-ray diffraction results reveal that NVP-Tix have same rhombohedral structure as NVP but shrunk lattice parameters. Pair distribution function spectra and the calculated crystal structure suggest that the local structural distortion of the doped samples originates from slight decrease of V‒O bond. As SIB cathode materials, greatly enhanced structural stability and electrochemical performance are achieved by Ti substitution. Especially, NVP-Ti0.15/C exhibits excellent rate capability and cyclability with capacity retention of 60% after 2000 cycles at high rate of 10 C. Importantly, even at 20 C, a reversible capacity of 63 mAh g−1 is maintained after 300 cycles at elevated temperature of 60 °C. Density functional theory calculations demonstrate that the superior electrochemical performance of the Ti-doped samples can be attributed to the enhanced intrinsic electronic conductivity, low Na+ diffusion energy barrier and high structural stability.

NaTi2(PO4)3 (NTP) with a sodium superionic conductor three-dimensional (3D) framework is a promising anode material for sodium-ion batteries (SIBs) because of its suitable potential and stable structure. Although its 3D structure enables high Na-ion diffusivity, low electronic conductivity severely limits NTP's practical application in SIBs. Herein, we report porous NTP/C nanofibers (NTP/C-NFs) obtained via an electrospinning method. The NTP/C-NFs exhibit a high reversible capacity (120 mA h g-1 at 0.2 C) and a long cycling stability (a capacity retention of ∼93% after 700 cycles at 2 C). Furthermore, sodium-ion full cells and hybrid sodium-ion capacitors have also been successfully assembled, both of which exhibit high-rate capabilities and remarkable cycling stabilities because of the high electronic/ionic conductivity and impressive structural stability of NTP/C-NFs. The results show that the nanoscale-tailored NTP/C-NFs could deliver new insights into the design of high-performing and highly stable anode materials for room-temperature SIBs.

Advances in developing affordable batteries are vital for integrating renewable and environmentally friendly energy sources into the power grid. Benefiting from the abundance of sodium resources, sodium-ion batteries (SIBs) have attracted great attention as one of the most promising energy storage and conversion devices for grid-scale energy storage systems. From this perspective, we present a succinct and critical survey of the emerging electrode materials, such as layered transition-metal oxides, polyanionic compounds, Prussian blue analogue cathode materials, and hard carbon anode materials, that have potential value for large-scale applications.

A novel solid sodium-ion conductor, Na2Mg2TeO6 (NMTO) with a P2-type honeycomb-layered structure, has been synthesized for the first time by a simple solid-state synthetic route. The conductor of NMTO exhibits high conductivity of 2.3 × 10-4 S cm-1 at room temperature (RT) and a large electrochemical window of ∼4.2 V (versus Na+/Na). The conductor is remarkably stable, both in the ambient environment and within its metallic Na anode. This facile sodium-ion conductor displays potential for use in all-solid-state sodium-ion batteries (SS-SIBs).

Sodium iron hexacyanoferrate (Fe-HCF) has been proposed as a promising cathode material for sodium-ion batteries (SIBs) because of its desirable advantages, including high theoretical capacity (∼170 mAh g–1), eco-friendliness, and low cost of worldwide rich sodium and iron resources. Nonetheless, its application faces a number of obstacles due to poor electronic conductivity and structural instability. In this work, Fe-HCF nanospheres (NSs) were first synthesized and fabricated by an in situ graphene rolls (GRs) wrapping method, forming a 1D tubular hierarchical structure of Fe-HCF NSs@GRs. GRs not only provide fast electronic conduction path for Fe-HCF NSs but also effectively prevent organic electrolyte from reaching active materials and inhibit the occurrence of side reactions. The Fe-HCF NSs@GRs composite has been used as a binder-free cathode with a capacity of ∼110 mAh g–1 at a current density of 150 mA g–1 (∼1C), the capacity retention of ∼90% after 500 cycles. Moreover, the Fe-HCF NSs@GRs cathode ...

Carbonaceous electrode materials for potassium-ion batteries (KIBs) are attractive due to the abundant resource of potassium and their rational capability. However, their rate capability and cycle life are mainly hindered by the intercalation chemistry involving repeated potassium insertion/extraction that are difficult to maintain within a short time or long-term cycling. Here, for the first time, a seafood waste (chitin)-derived hierarchically porous nitrogen-doped carbon microsphere (NCS) electrode with a surface-driven potassium storage mechanism is developed. The NCS electrode demonstrates a record high rate capability of 154 mA h g−1 at 72 C and ultralong cycle life of 4000 cycles without obvious capacity decay (180 mA h g−1 at 1.8 C), representing the best rate capability and longest cycle life among all electrodes in KIBs and even supassing most electrodes in sodium-ion batteries (NIBs). Further kinetic analysis and first-principle calculations reveal the dominated capacitive surface-driven mechanism of potassium storage in NCS, which is attributed to the hierarchically porous microstructure and nitrogen-doped carbon structure with enhanced potassium adsorption capability and electronic/ionic conductivities.

Considerable attention has been paid to sodium-ion batteries (SIBs) for large-scale energy storage due to low cost and abundant Na source. Phosphorus (P) is proposed as a high-capacity SIB anode material with theoretical capacity of 2596 mAh g −1 . However, the large volume expansion of P during sodiation brings about a series of challenges, including rapid capacity decay and slow ion transport. In this work, we develop an amorphous P ( α P) anode material with cubic boron nitride (c-BN) as a mechanical skeleton wrapped by nanoporous graphene (pGra) networks, which can combine synergistically the advantages of pGra and c-BN, and hence simultaneously solve the challenges for the P-based anodes. The rigid nature of c-BN is effective to suppress the severe volume expansion during P sodiation process, while the porous network of pGra serves as transport channel for electrons and ions, offering short pathways for large-radii Na + ions diffusion. The α P/c-BN/pGra composite anode shows excellent cyclability with a stable specific capacity of ∼1000 mAh g −1 and ∼90% capacity retention after 100 cycles at a specific current of 50 mA g −1 . The rigid c-BN and flexible pGra provides a promising pathway for developing high performance alloy-based materials for low-cost SIBs.

As an anode material for sodium-ion batteries (SIBs), hard carbon (HC) presents high specific capacity and favorable cycling performance. However, high cost and low initial Coulombic efficiency (ICE) of HC seriously limit its future commercialization for SIBs. A typical biowaste, mangosteen shell was selected as a precursor to prepare low-cost and high-performance HC via a facile one-step carbonization method, and the influence of different heat treatments on the morphologies, microstructures, and electrochemical performances was investigated systematically. The microstructure evolution studied using X-ray diffraction, Raman, Brunauer–Emmett–Teller, and high-resolution transmission electron microscopy, along with electrochemical measurements, reveals the optimal carbonization condition of the mangosteen shell: HC carbonized at 1500 °C for 2 h delivers the highest reversible capacity of ∼330 mA h g–1 at a current density of 20 mA g–1, a capacity retention of ∼98% after 100 cycles, and an ICE of ∼83%. Additionally, the sodium-ion storage behavior of HC is deeply analyzed using galvanostatic intermittent titration and cyclic voltammetry technologies.

Sodium-ion batteries (SIBs) have shown extensive prospects as alternative rechargeable batteries in large-scale energy storage systems, because of the abundance and low cost of sodium. The development of high-performance cathode and anode materials is a big challenge for SIBs. As is well known, TiNb2O7 (TNO) exhibits a high capacity of ∼250 mAh g–1 with excellent capacity retention as a Li-insertion anode for lithium-ion batteries, but it has rarely been discussed as an anode for SIBs. Here, we demonstrate ball-milled TiNb2O7 (BM-TNO) as an SIB anode, which provides an average voltage of ∼0.6 V and a reversible capacity of ∼180 mAh g–1 at a current density of 15 mA g–1, and presents excellent cyclability with 95% capacity retention after 500 cycles at 500 mA g–1. A possible Na storage mechanism in BM-TNO is also proposed.

Currently, it is a great challenge to find suitable electrode materials for sodium-ion batteries (SIBs) with large capacity, long cycle life, and high rate capability. Herein, we report a new layered titanate, Na2Li2Ti5O12 (NLT), derived from K2Li2Ti5O12 (KLT) via an ion-exchange method as a SIB anode material. KLT is prepared by a low-temperature solid-state reaction and then transformed into NLT by replacing potassium with sodium in a NaCl solution at room temperature. NLT provides a sodium-ion intercalation voltage at ∼0.5 V versus Na/Na+ and a reversible capacity of 175 mA h g−1 at a current density of 100 mA g−1. It also shows a high sodium-ion diffusion coefficient of 3.0 × 10−10 cm2 s−1, ensuring a high rate capability. For NLT, extremely high discharging rate capability is achieved with a capacity of more than 80 mA h g−1 at a 60 second full discharge and even with 70 mA h g−1 at a 34 second charge. Kinetics analysis based on cyclic voltammogram reveals a typical sodium-ion intercalation behavior in NLT. Furthermore, the first-principle calculation shows a lower migration energy barrier for sodium ions in NLT than that in other layered titanates. These results suggest that NLT is a very promising anode material for high-performance SIBs, especially for fast-charging stable SIBs.

High-capacity silicon-based anode materials with high conductivity to promote electron/ion transfer and excellent elasticity to alleviate volume expansion during repeated lithiation/delithiation process are highly desirable for next-generation lithium-ion batteries. Herein, we developed a facile in situ synthesis method based on chemical vapor deposition to fabricate Si-based nanocomposites integrated with interlinked graphene (Gra) and carbon nanotube (CNT). With melt-assembly nanosized Cu as the catalyst, hierarchical three-dimensional conductive Gra/CNT networks were in situ grown onto Si nanoparticles (SNPs) to achieve the Si@Gra@CNT composite. Such a hierarchical structure combines multiple advantages from SNPs with a super high capacity, Gra/CNT framework with continuous electrical conductivity, and void space for tolerance of Si volume expansion. Moreover, the SNPs were conformally encapsulated by few-layer Gra (fGra), which can protect the SNPs from direct exposure to electrolyte, resulting in a stable solid–electrolyte interface. As an anode material for Li-ion battery, the as-prepared Si@Gra@CNT composite exhibited a high initial specific capacity of 1197 mA h g−1 at a current density 2.0 A g−1 and ∼82% capacity retention over 1200 cycles, which was much better than those of Si@Gra and Si@CNT composites. The mechanism for the improved electrochemical performance was further analysed from the aspect of the synergetic effect arising from the construction components.

Fast and accurate test Cr(VI) in the whole blood is particularly critical for the treatment and prevention of Cr(VI) poisoning. Here, a blood compatible, high-efficient sensor based on the magnetic glassy carbon electrode (MGCE) that modified by conductive polyaniline (PANI), heparin and tannin modified Fe3O4 nanoparticles (magnetic tannin-modified adsorbent, MTA) with high adsorption ability toward Cr(VI) ions was developed. Results indicated the designed PANI/Hep/MTA/MGCE exhibited high sensitivity for Cr(VI) in the concentration range of 10−7 to 10−4 ppm with a 0.87 μM detection limit (3σ method). In particular, this prepared sensor not only exhibited outstanding electrochemical performance for Cr(VI) detection, but also possessed good antibiofouling characteristics due to the existence of heparin, which can provide guarantee for direct detection of Cr(VI) in the whole blood.

In this study, the shape recovery and mechanical properties of Ni54Mn16Fe9Ga21 high-temperature shape memory alloy are improved simultaneously. This results from the low, about 4.4%, volume fraction of γ phase being almost completely distributed along grain boundaries. The recovery strain gradually increases with the increase in residual strain with a shape recovery rate of above 68%, up to a maximum value of 5.3%. The compressive fracture strain of Ni54Mn16Fe9Ga21 alloy is about 35%. The results further reveal that when applying a high compression deformation two types of cracks form and propagate either within martensite grains (type I) or along the boundaries between martensite phase and γ phase (type II) in the present two-phase alloy.

The high specific capacity battery electrode materials have stimulated great research interest. Silicon (Si) as a low-cost abundant material with a theoretical specific capacity of 4200 mA h g −1 , offers an attractive option for the low-cost next-generation high capacity Li-ion batteries anode. However, successful applications of silicon anode have been impeded by several limitations such as large volume expansion (400%) with lithiation, poor conductivity and unstable solid electrolyte interphase (SEI) with cycles. To address these challenges, we engineered Si nanoparticles by encapsulating them with monolayer graphene (mGra) with empty space generated by melt-self-assembly Cu layer. Here, a new method is introduced to uniform encapsulate the nano-silicon particles. The synthesis process used low-cost Si nanoparticles and Cu foils via chemical vapor deposition methods. The mGra and void space around the Si nanoparticles guaranteed to overcome mentioned problems. The flexibility nature and high conductivity of mGra effectively accommodate the Si volume expansion associated with the lithiation, and function as charges fast channels that allow for ions and electrons transport in fast kinetics. Most important, the crystalized mGra layer served as a flexible protective layer avoiding the SNPs direct exposed to electrolyte, which boosted the formation of stable and thin SEI interface. Our anode demonstrated a high initial coulomb efficiency (CE) 85% with gravimetric capacity ~1450 mA h g −1 (based on the total mass) and long cycle life (500 cycles with 89% capacity retention). Such SNP@void@mGra structure orienting excellent cycle life and high charge capacity provide a promising prospect for the next-generation high specific energy battery.

Primer helps to enhance the adhesive force of the tape and the substrate. Different reinforcements on different substrates have different amplitudes. The order of increase in initial bond strength is PC> PVC> PP> PET>> PE. The order of increasing holding power after 7 days is PP> PVC> PC> PET>> PE. The primer has better adhesion on the modified tape than on the unmodified tape. High temperature and humidity are not conducive to the enhancement of the primer. The polar substrate has a more pronounced reinforcing effect. Ultraviolet (UV) irradiation can initiate group polymerization cross-linking to increase the tackiness. With the increase of irradiation power, the adhesive strength of the adhesive layer gradually increased and reached stability at around 3000mJ. The effect of ultraviolet irradiation on the shearing force of the adhesive tape on the glass substrate is significant,the decrease is greater than 60%. With the increase of the irradiation power, the maximum deformation of the tape decreased, and the rebound rate remarkably increased from 10.7% to 62.5%.