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Modifying separator with metal oxides has been considered as a strong strategy to inhibit the shuttling of soluble polysulfide in the lithium-sulfur battery (Li-S battery). Manganese dioxide (MnO2), one kind of transition metal oxide, is widely applied to decorate the PP (Polypropylene) separator. However, the fabrication by physical coating is always multistep and complicated. Here, we design a simple and fast method to chemically decorate separator. Based on the oxidizing property of acidic KMnO4 solution, the PP separator was oxidized and an ultrathin self-assembled MnO2 layer was directly constructed on one side of separator, by immersing in acidic KMnO4 solution for only 1 h. The self-assembled MnO2 layer has the synergistic effect of adsorption and catalytic conversion on polysulfides, which can effectively inhibit the shuttle effect. It can also help battery to maintain excellent electrochemical kinetics in the electrochemical cycle and maintain the effective recycling of active substances. As a result, the shuttling of polysulfide is greatly prohibited by this novel functional separator, and cycling stability is outstandingly improved, with a low-capacity decaying of 0.058% after 500 cycles at 0.5C. The rapid and simple modification method proposed in this study has a certain reference value for the future large-scale application of lithium-sulfur battery.

The introduction of spinel phase to form the layered-spinel structure (LSS) is an effective way to improve the electrochemical performance of Li- and Mn-rich layered oxides (LMR). But is this structure universal for all LMR systems? In this work, different Mn/Ni ratio systems with the LSS are discussed in detail. It is found that, high discharge capacity (200.8 mA h g−1 at 1C rate; 1C = 250 mA h g−1) as well as high capacity-retention (94% at 1C rate after 100 cycles) can be achieved by forming the LSS for low-Ni system (Mn/Ni = 5.0). However, the capacity retention decreases severely in the high-Ni system (Mn/Ni = 3.5, 2.6). For example, when the ratio of Mn/Ni is 3.5, the capacity-retention of the layered-spinel sample was only 65.8%, compared to the 83% of the original LMR sample. The Ex-situ XRD, XPS, and HRTEM results demonstrate that the introduction of spinel phase in high-Ni system accelerates the transition and collapse of the crystal structure. This work provides guidance for optimizing the proportions of elements and the design of structures for the LMR.

Li-rich layered oxides with high capacity are expected to be the next generation of cathode materials. However, the irreversible and sluggish anionic redox reaction leads to the O2 loss in the surface as well as the capacity and voltage fading. In the present study, a simple gas-solid treatment with ferrous oxalate has been proposed to uniformly coat a thin spinel phase layer with oxygen vacancy and simultaneously realize Fe-ion substitution in the surface. The integration of oxygen vacancy and spinel phase suppresses irreversible O2 release, prevents electrolyte corrosion, and promotes Li-ion diffusion. In addition, the surface doping of Fe-ion can further stabilize the structure. Accordingly, the treated Feox-2 % cathode exhibits superior capacity retention of 86.4 % and 85.5 % at 1 C and 2 C to that (75.3 % and 75.0 %) of the pristine sample after 300 cycles, respectively. Then, the voltage fading is significantly suppressed to 0.0011 V per cycle at 2 C especially. The encouraging results may play a significant role in paving the practical application of Li-rich layered oxides cathode.

As a secondary Li-ion battery with high energy density, lithium-sulfur (Li-S) batteries possess high potential development prospects. One of the important ingredients to improve the safety and energy density in Li-S batteries is the solid-state electrolyte. However, the poor ionic conductivity largely limits its application for the commercial market. At present, the gel electrolyte prepared by combining the electrolyte or ionic liquid with the all-solid electrolyte is an effective method to solve the low ion conductivity of the solid electrolyte. We present a cross-linked gel polymer electrolyte with fluoroethylene carbonate (FEC) as a solid electrolyte interface (SEI) film formed for Li-S quasi-solid-state batteries, which can be simply synthesized without initiators. This gel polymer electrolyte with FEC as an additive (GPE@FEC) possesses high ionic conductivity (0.830 × 10-3 S/cm at 25 °C and 1.577 × 10-3 S/cm at 85 °C) and extremely high Li-ion transference number (tLi+ = 0.674). In addition, the strong ability toward anchoring polysulfides resulting in the high electrochemical performance of Li-S batteries was confirmed in GPE@FEC by the diffusion experiment, X-ray photoelectron spectroscopy analysis (XPS), and scanning electron microscopy (SEM) mapping of the S element. Such a high ion conductivity (IC) gel polymer electrolyte enables a competitive specific capacity of 940 mAh/g at 0.2C and supreme cycling performance for 180 cycles at 0.5C, which is far beyond that of conventional poly(ethylene oxide)-based quasi-solid-state Li-S batteries.

Li-rich Mn-based cathodes have attracted much attention due to their high capacity stemming from anion redox above 4.5 V. However, the continuous activation of Li2MnO3 in Li-rich Mn-based materials, which correlates with O2 release and TM migration, is usually unfavorable to structural stability. Herein, based on a gas-solid interface reaction, we tackle this continuous activation phenomenon by restricting the capacity release of Li2MnO3 via NH4HCO3 treatment in the Li1.2Ni0.36Mn0.44O2 cathode. After modification, oxygen vacancies associated with the spinel phase are introduced on the surface. The 4 mol % NH4HCO3-modified material's capacity starts at 182 mAh g-1 at 1 C instead of increasing from 173 to 186 mAh g-1 for 25 cycles in the pristine material. Meanwhile, it also exhibits an excellent capacity retention of 93.24% after 200 cycles (at 1 C), with a small voltage decay rate of 1.19 mV cycle-1.

The continuous growth of the solid-electrolyte interface (SEI) and material crushing are the fundamental issues that hinder the application of Ge anodes in lithium-ion batteries. Solving Ge deformation crushing during discharge/charge cycles is challenging using conventional carbon coating modification methods. Due to the chemical stability and high melting point of carbon (3500 °C), Ge/carbon hybridization at the atomic level is challenging. By selecting a suitable carbon source and introducing an active medium, we have achieved the Ge/carbon doping at the atom-level, and this Ge/carbon anode shows excellent electrochemical performance. The reversible capacity is maintained at 1127 mAh g-1 after 1000 cycles (2 A g-1 (2-71 cycles), 4 A g-1 (72-1000 cycles)) with a retention of 84 % compared to the second cycle. The thickness of the SEI is only 17.4 nm after 1000 cycles. The excellent electrochemical performance and stable SEI fully reflect the application potential of this material.

Binders have been confirmed to play a significant role in improving the cycling performance of Si anode. Some of natural biogum binders are exploited and related progresses are also achieved. However, the distinction of characteristics among different biogum binders as well as corresponding mechanisms and principles still remain to be elucidated. In this study, gum arabic (GA), guar gum (GG), and xanthan gum (XG) are selected for comparison. The highest initial Coulombic efficiency (ICE) of 90.4% is obtained with GA owing to diverse multiple interactions with Si nanoparticles to form a homogeneous covering that could protect Si core against being exposed to electrolyte and generating SEI film, as well as strong covalent network to suppress the isolation of Si, while plastic damage occurs during repeated volume change of Si because of irreversible bonding nature. By contrast, hydrogen bonding between polar –OH groups with self-healing nature provides Si anodes with GG and XG better cycling stability, while the optimized capacity of 1323 mAh g−1 after 100 cycles is retained with GG due to the extra ability to transfer Li+. This study provides the design and selection principles for binders applied in Si anodes of lithium-ion batteries.

A binder is an important component in lithium-ion batteries and plays a significant role in maintaining the properties of active substances. Most studies in the field of binders have only focussed on physical properties such as bonding performance. Here, a polyacrylic acid-modified binder was designed and adapted to Li[Ni0.8Co0.1Mn0.1]O2, which enhanced the electrochemical stability of Li[Ni0.8Co0.1Mn0.1]O2 from 30.2 to 66.6% (300 cycles at 1 C). We for the first time discovered that this was caused by a chemical reaction between polyacrylic acid and the residual lithium on the surface during the cycling, which formed a lithium propionic acid coating layer and maintained the stability of the layered structure.

Motivated by attributes including environmental hazards and resource value, the recycling of the spent graphite has aroused increasing attention. Meanwhile, a silicon/graphite composite has been considered as a promising high-capacity anode for lithium-ion batteries. However, uniform dispersion and outperformed stability of silicon (Si) particles in the graphite matrix still remain a great challenge. Current solutions mainly focus on the design of Si nanostructures and the overall architecture of the silicon/graphite composite, while little attention has been paid to the graphite matrix. Herein, the Si/spent graphite (Si/SG) composite was prepared based on the recycling of SG. The SG was in situ modified during the battery cycling process and formed unique physicochemical properties. By spontaneously tuning the zeta potential, the electrostatic force integrated the Si nanoparticles within the SG matrix to restrain the volume strain upon lithiation/delithiation. Besides, defect-enriched and exfoliated SG can effectively enhance the electric conductivity, facilitating the electrochemical kinetics in the electrodes. What is more, the oxygen-containing functional groups on the SG could adjust the solid electrolyte interphase (SEI) component by generating more organic components to improve the mechanical toughness of the SEI layer. Consequently, the Si/SG composite electrode delivers a high initial discharge capacity of 1321.8 mA h g−1 at 0.05 A g−1 and stable cycle life with a capacity retention of 69% at 1 A g−1 after 400 cycles. The proposed composite may provide some guidelines for improving the interface stability of the Si/graphite anode and simultaneously the high-value application of spent graphite.

Recycling and reusing spent graphite have become urgent tasks, with massive numbers of lithium-ion batteries (LIBs) from hybrid electric vehicles (HEVs)/electric vehicles (EVs) retired every year. Meanwhile, interlayer designs based on carbon materials have attracted widespread attention to suppress the polysulfide shuttle effect in high-energy-density lithium–sulfur (Li–S) batteries. Nevertheless, designing simple and low-cost carbon-derived interlayers still remains a great challenge. Spent graphite possesses a porous structure, defects, and polar functional groups that were formed in situ, which can significantly confine polysulfides through a combination of physical and chemical adsorption. Meanwhile, transition metals introduced due to the dissolution of cathode active materials can also anchor polysulfides via S–TM bonding, as well as improving electrical conductivity and boosting polysulfide conversion kinetics. Herein, spent graphite recycled from waste LIBs was employed for the first time as a functional interlayer for Li–S batteries based on its intrinsic properties. The spent-graphite-derived interlayer exhibited remarkably enhanced trapping and catalytic performance toward polysulfides. A high discharge capacity of 968 mA h g−1 with a low decay rate of 0.08% per cycle over 500 cycles at 1 C can be obtained. The present work not only provides a promising strategy for the design of interlayers, but it also shows a high-value application of spent graphite.

Sodium-ion batteries (SIBs) have shown promising prospects for complementarity to lithium-ion batteries (LIBs) in the field of grid-scale energy storage. After a decade of continuous fundamental research on SIBs, it's becoming increasingly urgent to advance the commercialization. For SIB anode materials, hard carbon is the most mature and currently the only material likely to be commercialized, but it is still far away from large-scale industrialization. Herein, we carry out a comprehensive overview of the current state of the art in terms of three main aspects. Firstly, a fundamental understanding of the microstructure and sodium storage mechanism of hard carbon is introduced, which can be categorized into three different processes: capacitive adsorption, nanopore filling, and intercalation in carbon interlayers. Then, based on an in-depth understanding of the sodium storage mechanism, optimization methods in terms of increasing the specific capacity, rate performance, initial coulombic efficiency (ICE), and long-cycling stability are comprehensively summarized and analyzed. Finally, potential methods and associated benefits for the design of carbon structures and the solid electrolyte interface (SEI) are discussed, hoping to provide useful guidelines for future research and commercialization.

Reducing the interfacial resistance between solid electrolytes and electrodes is critical for developing high-energy density solid-state batteries. In the present study, a simple strategy of designing an integrated cathode and solid electrolyte (ICSE) to avoid a contact interface is proposed and successfully fulfilled with the help of UV curving. Firstly, a porous polymer film (PVDF-HFP/PVDF) was formed on the surface of the porous LiFePO4 electrode via PVP dissolution. Secondly, curable monomers, including PEGDA/PETMP/TFEMA, were filled into the porous membrane via infiltration and concentration. Lastly, the ICSE was obtained via curing with ultraviolet light. The as-prepared LiFePO4//ICSE//Li solid battery displays excellent electrochemical performance with a high reversible capacity of 153 mA h g-1 and a capacity of over 140 mA h g-1 was retained after 150 cycles at 0.1C and 25 °C. This ICSE strategy may effectively contribute to the practical application of all-solid-state batteries.

Ni-rich lithium nickel cobalt aluminum oxide (NCA) cathodes, as one of the most promising candidates for the extended electric vehicle applications, have been widely recognized and attracted global...

Energy storage devices are indispensable for supporting human activities; thus, producing sustainable environmental energy is a current focus of attention. Lithium–sulfur batteries (Li–S batteries)...

N-doped straw sheaf–like porous MnO@C composite is synthesized through a L-histidine-assisted hydrothermal method with consequent annealing in Ar. The straw sheaf–like porous structure is assembled by MnO nanoparticles with a diameter of ~ 15 nm and be uniformly wrapped in amorphous N-doped carbon matrix. MnO@C-N displays attractive electrochemical properties when used as anode of lithium-/sodium-ion batteries. A high reversible capacity of 832.5 mA h g−1 could be obtained at 100 mA g−1 in LIBs and 250 mA h g−1 at 50 mA g−1 with outstanding cycling stability in SIBs. The study also compared MnO@C-N with commercial MnO particles in LIBs and shows that MnO@C-N anode has excellent cycling performance with 614.0 mA h g−1 retained after 200 cycles. However, commercial MnO displays only 413.5 mA h g−1 after 132 cycles. The present synthesis strategy opens the possibility of fabricating MnO@C-N nanocomposites for high-performance batteries.

Lithium-rich cathode oxides exhibit extraordinary specific capacities that are mainly ascribed to the accumulated redox reactions of anions and cations at high operating potentials. However, rapid ...

The Ni-rich cathodes are considered as the next generation candidate cathode material of lithium-ion batteries due to the high-energy–density and environmentally friendly. Unfortunately, the cathodes are up against severe structure instability at the repeated charge/discharge process, resulting in the attenuation of voltage and capacity. Herein, we proposed a novel strategy with uniform Al and Ti cations co-doping of LiNi0.8Co0.1Mn0.1O2 cathode. The modification strategy not only stabilizes the vulnerable layered structure but also mitigate voltage/capacity attenuation at different cutoff voltages. As a result, the modified cathode with trace content of Al and Ti cations co-doping can broaden the lithium ions diffusion channels, mitigate the structural collapse, and unfavorable phase transformation to some extent. Specifically, the modified sample exhibits remarkable enhanced electrochemical performance in discharge capacity and voltage retention of 76.75%, 98.78% at 1 C after 200 cycles. Even though at elevated voltage, the modified sample shows improved cycle life with a capacity retention of 70.93% after 200 cycles.

The increased application of layered oxide (LiCoO2) lithium ion batteries (LIBs) for electronic products will result in lots of spent layered cathodes in the near future. Furthermore, the explorati...

CoNi-contained nanosheets can be prepared by dealloying CoNiAl alloys in aqueous NaOH solution in the presence of H2O2, and upon annealing sample exhibits dendritic NiCo2O4 micro-nanostructure. The effect of H2O2 solution on the structure, morphology, and electrochemical performances of the resulting products is studied systematically. These results indicate that the H2O2 solution mainly influences the morphology of the NiCo2O4. When tested as anode materials for lithium-ion batteries (LIBs), the obtained NiCo2O4 sample shows high specific capacity, excellent rate property, and superb cycling stability. A reversible capacity is still maintained at 1016.9 mAh/g after 100 cycles at a current density of 100 mA/g. Even at a current rate of 1000 mA/g, the capacity can reach to 691.4 mAh/g. The outstanding electrochemical properties of the NiCo2O4 anode make them promising anode materials of LIBs and other energy storage applications.

Metal sulfides with high capacity have been considered as candidates for efficient sodium-ion storage. However, their undesirable rate capability and fast capacity fading hinder their commercial applications. Herein, we prepared a platelet-like CuS material with twin crystals. The edges of the platelet are composed of single crystal structures, and the interior of platelet contains twin crystal structures. Due to its structural and compositional advantages, this platelet-like CuS material with twin crystal structures manifests superior rate performance (420 mA h g−1 at 0.05 A g−1 and 277 mA h g−1 at 5 A g−1) and excellent cycling stability without capacity decay after around 500 cycles at 2 A g−1.

In practice, high fidelity fluorescence imaging in vivo faces many issues, for example: (1) the fluorescence background of the probe is bleached by the wide intensity scale of fluorescence microscopy, displaying an inherent false negative background (FNB); and (2) the dosage of the probe has to be increased to achieve sufficient intensity for in vivo imaging, causing a vicious cycle that exacerbates the FNB. Herein, we constructed a fluorophore (F)–electron donor (D)–electron regulator (R) system, and thereby developed a dual modulation strategy for the de novo design of high fidelity probes. Using cross-talk modulation, the probe allows: (1) enhanced ESET (excited state electron transfer) from F to D, which minimizes the inherent FNB based on synergistic PET (photo induced electron transfer); and (2) the inhibition of PET and weakening of ESET from F to D to maximize the reporting intensity to further reduce the FNB, which is additionally enhanced by an overdose of the probe. To test the implementation, we constructed a 7-hydroxy-2-oxo-2H-chromene-3-carbaldehyde (HPC) series of probes, with HPC (F) as the fluorophore, 2-hydrazinylpyridine, which was screened as an electronically adjustable donor (D), and electronic regulators (R). In particular, HPC-7 and HPC-8 provided cell/zebrafish imaging with negligible background even using the rather low fluorescence scale of microscopy (a region for revealing hidden background). Interestingly, with the specificity of HPC for reporting zinc, we achieved probe HPC-5, which possesses both an ultralow inherent FNB and optimal reporting intensity for tissue and in vivo imaging, enabling the in vivo imaging of zinc in mice for the first time. Under this high-fidelity mode, the fluorescence monitoring of zinc ions during the development of liver cancer in mice was successfully performed. We envision that the dual modulation strategy with the F–D–R system could provide a useful concept for the de novo design of practical probes., We engineered a cross-talk electron transfer strategy using an F–D–A system to reduce the false negative background for high fidelity imaging in vivo.

High‐capacity layered oxide Ni‐rich cathodes are attractive to enhance the driving‐range of electric vehicles because of its preferential costs. Nevertheless, in Ni‐rich cathodes, there are still many issues such as microcracks generation along grain boundaries and interface side reaction between active substance and electrolyte, resulting in the rapidly deterioration of electrochemical property. Herein, improving the performance of Ni‐based cathodes by structural regulation is summarized. The remaining challenges and outlook are discussed as well.

In order to determine trace impurities in the nuclear grade UF4, an analysis method based on the standard addition and 103Rh internal standardization techniques combined with ICP-MS has been established. The examination tests, including comparison with the quantity of trace impurities assigned in a certified reference uranium oxide and determination of the standard addition recovery, were performed to validate the accuracy and precision of the method. Total 42 trace impurity elements from Li to Bi were determined, with the method detection limit for the 42 impurities were found in the range of 0.0004–0.072 μg g−1. The recoveries were varied from 92% to 111%, and the relative deviations for most of the impurity elements were less than 10%. The method has been verified to meet the requirements of quality control for the UF4 and will be used in the molten salt reactor.

A novel efficient photoelectrochemical (PEC) sensor was assembled for curcumin (Cur) detection using 2-mercaptoacetic acid (TGA)-capped CdTe nanoparticles and nickel tetra-amined phthalocyanine-linked graphene oxide (TGA-CdTe@NiTAPc-Gr). The TGA-CdTe nanoparticles could be firmly immobilized on the thin film structure of NiTAPc-Gr in a hydrogen-bonded manner, thus producing the proposed PEC sensor with a high photoelectrochemical activity of TGA-CdTe nanoparticles and excellent stability of NiTAPc-Gr. The TGA-CdTe@NiTAPc-Gr thin film showed a stronger blue light absorption property than the individual precursors, and this resulted in the sensitive detection of Cur ranging from 0.25–100 μM with a detection limit of 12.50 nM. In addition, the PEC sensor exhibited a high sensitivity and selectivity and quite good reproducibility. Thus, it shows potential for Cur detection in real samples.

Three kinds of Cu-Sn alloy anodes with different current collectors for lithium ion batteries had been directly prepared by cost-effective and easy to scale-up electro-deposition method. Both the self-standing electrode and the electrode with polypyrrole (PPy) current collector had effects on enhancing the cycle stability and increasing the gravimetric energy density. However, due to the poor conductivity of PPy and the low crystallinity structure of Cu-Sn alloy layer, the high rate performance of Cu-Sn alloy electrode with PPy current collector was unsatisfactory, while the self-standing electrode not only greatly increased the cycle stability and energy density of the whole electrode to a large extent, but also exhibited superior high-current cycle performance. Even cycled at a current density of 6 A g−1 after 700 cycles, the self-standing electrode could still maintain a specific capacity of 332 mA h g−1, which illustrated the potential application prospect of self-standing electrode with higher energy density and power density.

Thermochemical cycles have been predominantly used for energy transformation from heat to stored chemical free energy in the form of hydrogen. The thermochemical cycle based on uranium (UTC), proposed by Oak Ridge National Laboratory, has been considered as a better alternative compared to other thermochemical cycles mainly due to its safety and high efficiency. UTC process includes three steps, in which only the first step is unique. Hydrogen production apparatus with hectogram reactants was designed in this study. The results showed that high yield hydrogen was obtained, which was determined by drainage method. The results also indicated that the chemical conversion rate of hydrogen production was in direct proportion to the mass of Na2CO3, while the solid product was Na2UO4, instead of Na2U2O7. Nevertheless the thermochemical cycle used for hydrogen generation can be closed, and chemical compounds used in these processes can also be recycled. So the cycle with Na2UO4 as its first reaction product has an advantage over the proposed UTC process, attributed to the fast reaction rate and high hydrogen yield in the first reaction step. Keywords: Thermochemical cycle, Hydrogen production, Uranium, Sodium urinate, Energy

Herein, nonstoichiometric structured tin-based anodes for lithium-ion batteries were directly prepared by a simple and traditional electrodeposition method. These tin-based anodes show high electrode capacity, excellent rate performance, and superior stable cycling stability, which delivers an outstanding reversible capacity of 728 mAh g–1 at the current density of 100 mA g–1 after 400 cycles. When cycled at the current density of 6 A g–1 for 250 cycles, the capacity of the tin-based anode was kept at about 300 mAh g–1. The tin-based anode with its nonstoichiometric structure can effectively overcome the volume expansion, stabilize the electrode structure, and enhance the cyclic stability through structural reconstruction. By improving the traditional preparation method, the excellent electrochemical anode can be obtained, which may greatly promote the commercial application of alloy mechanism anode materials in lithium-ion batteries.

Neuromorphic computing holds promise for building next-generation intelligent systems in a more energy-efficient way than the conventional von Neumann computing architecture. Memristive hardware, which mimics biological neurons and synapses, offers high-speed operation and low power consumption, enabling energy- and area-efficient, brain-inspired computing. Here, recent advances in memristive materials and strategies that emulate synaptic functions for neuromorphic computing are highlighted. The working principles and characteristics of biological neurons and synapses, which can be mimicked by memristive devices, are presented. Besides device structures and operation with different external stimuli such as electric, magnetic, and optical fields, how memristive materials with a rich variety of underlying physical mechanisms can allow fast, reliable, and low-power neuromorphic applications is also discussed. Finally, device requirements are examined and a perspective on challenges in developing memristive materials for device engineering and computing science is given.

Vanillin is widely used as a flavor enhancer and is known to have numerous other interesting properties, including antidepressant, anticancer, anti-inflammatory, and antioxidant effects. However, as excess vanillin consumption can affect liver and kidney function, simple and rapid detection methods for vanillin are required. Herein, a novel electrochemical sensor for the sensitive determination of vanillin was fabricated using an iron phthalocyanine (FePc)-based metal–organic framework (MOF). Scanning electron microscopy and transmission electron microscopy showed that the FePc MOF has a hollow porous structure and a large surface area, which impart this material with high adsorption performance. A glassy carbon electrode modified with the FePc MOF exhibited good electrocatalytic performance for the detection of vanillin. In particular, this vanillin sensor had a wide linear range of 0.22–29.14 μM with a low detection limit of 0.05 μM (S/N = 3). Moreover, the proposed sensor was successfully applied to the determination of vanillin in real samples such as vanillin tablets and human serum.

Metal sulfides have been intensively investigated for efficient sodium‐ion storage due to their high capacity. However, the mechanisms behind the reaction pathways and phase transformation are still unclear. Moreover, the effects of designed nanostructure on the electrochemical behaviors are rarely reported. Herein, a hydrangea‐like CuS microsphere is prepared via a facile synthetic method and displays significantly enhanced rate and cycle performance. Unlike the traditional intercalation and conversion reactions, an irreversible amorphization process is evidenced and elucidated with the help of in situ high‐resolution synchrotron radiation diffraction analyses, and transmission electron microscopy. The oriented (006) crystal plane growth of the primary CuS nanosheets provide more channels and adsorption sites for Na ions intercalation and the resultant low overpotential is beneficial for the amorphous Cu‐S cluster, which is consistent with the density functional theory calculation. This study can offer new insights into the correlation between the atomic‐scale phase transformation and macro‐scale nanostructure design and open a new principle for the electrode materials' design., A hydrangea‐like CuS microsphere with high geometrical symmetry and oriented (006) crystal plane growth is successfully constructed through a facile synthetic route. The oriented (006) crystal plane growth of the primary CuS nanosheets provide more channels and adsorption sites for Na ions intercalation, and the resultant low overpotential is beneficial for the amorphous Cu‐S cluster.

In hydrogen production industry, thermochemical cycle technology for converting thermal energy into chemical storage energy of hydrogen owns absolute advantages. Compared with other thermochemical cycles, thermochemical cycle technology based on uranium (UTC) is safer and more efficient. This technology consists of three steps, where only the hydrogen production step is unique. In this paper, the verification has been done for this step. Solid products were characterized by XRD and Raman spectroscopy, which were confirmed to be α-Na2U2O7. Gas chromatographic analyses were performed for gas samples, in which hydrogen output was obtained using an internal standard method.

High catalytic performance of a single-atom transition metal ion (TMx+) anchored on the two-dimensional (2D) C2N lattice is predicted for HCOOH dehydrogenation. Considering the Co2+, Cu2+ and Ni2+ non-noble metal ions supported by C2N, we use density functional theory to demonstrate dehydrogenation energy barriers as low as those for pure Pt and Pd catalysts. The high catalytic performance is ascribed to the reaction occurring through a dual-active center composed of TMx+ and a nearby N atom of C2N. Specifically, C2N–Co2+ in the low spin state (S = 1/2) greatly promotes HCOOH dehydrogenation by decreasing the barrier of the rate-determining step to only 0.30 eV, mainly due to the strong ability of TMx+ to extract charges from HCOOH and C2N. The obtained mechanistic insights help the rational design of single-atom based transition metal ion catalysts supported by 2D materials.

SiO2 is one of the critical raw materials for preparing Si anode. The direct use of porous Si made from SiO2 in LIBs is challenging. Although carbon cladding can improve the cycling performance of Si anode materials made from SiO2, the surface coating cannot address the comminution inside the material during repeated volume deformation. For the first time, we prepared an in-situ doped Si/carbon anode material that uses SiO2 and CO2 as Si and carbon sources and Mg as the reduction medium (Mg2Si + CO2 → MgO + Si + C). The in situ embedded carbon completes the nanosizing of Si (less than50 nm) and forms a three-dimensional (3-D) carbon network that enhances electrical conductivity and acts as a buffer layer. After 500 cycles at 0.5 A g−1, the discharge specific capacity is 912 mAh g−1, and the capacity still has 1487 mAh g−1 even at 4 A g−1. The simple method of preparing Si/carbon composite material in situ provides a new idea for modifying Si-based anode material and provides a valuable reference for carbon doping.

Silicon monoxide (SiO) has been explored and confirmed as a promising anode material of lithium-ion batteries. Compared with pure silicon, SiO possesses a more stable microstructure which makes better comprehensive electrochemical properties. However, the lithiation mechanism remains in dispute, and problems such as poor cyclability, unsatisfactory electrical conductivity, and low initial Coulombic efficiency (ICE) need to be addressed. Additionally, more attention needs to be paid on the internal relationship between electrochemical performances and structures. In this review, the different preparation processes, the derived microstructure of the SiOx , the corresponding lithiation mechanism, and electrochemical properties are summarized. Researches about disproportionation reaction which is regarded as a key point and other modifications are systematically introduced. Closely linked with structure, the advantages and disadvantages of various SiOx anode materials are summarized and analyzed, and the possible directions toward the practical applications of SiOx anode material are presented. In a word, from the preparation and reaction mechanism of the material to the modifications and future development, a complete and systematical review on SiOx anode is presented.

Shuttle effect is the core problem in lithium-sulfur battery, which makes internally poor dynamics and bad cycle stability of the lithium-sulfur battery (Li–S battery). In this study, a sheet nitrogen-doped vanadium dioxide material that roots in a metal-organic framework (SVO) was designed and synthesized. SVO has a unique two-dimensional structure and uniform distribution of metal sites. It leads to the adsorption-catalytic synergistic effect that can efficiently anchor polysulfides and promote sulfur conversion kinetics to significantly alleviate the shuttle effect. With the metal-organic framework precursor synthesized under mild conditions of room temperature and pressure, the SVO materials used to modify the separator can be simply obtained by calcination. Especially, the modified material exhibits excellent electrochemical performance with only 0.081% degradation of capacity per cycle at 1C after 500 cycles. Even under a harsh condition (sulfur loading = 6.3 mg cm−2, E/S = 5), the battery with SVO/AB separator is available to reach an area capacity of about 4.16 mAh cm−2 at 0.1C. Meantime, as for the anode side, SVO/AB separator can be used as lithium-ion guides to keep stable lithium-ion stripping/plating and inhibit the growth of lithium dendrite. The battery with SVO/AB separator also shows superior performance under high and low temperatures.

A fabrication strategy for biphasic gels is reported, which incorporates high-internal-phase emulsions. Closely packed micro-inclusions within the elastic hydrogel matrix greatly improve the mechanical properties of the materials. The materials exhibit excellent switchable mechanics and shape-memory performance because of the switchable micro- inclusions that are incorporated into the hydrogel matrix. The produced materials demonstrated a self-healing capacity that originates from the noncovalent effect of the biphasic heteronetwork. The aforementioned characteristics suggest that the biphasic gels may serve as ideal composite gel materials with validity in a variety of applications, such as soft actuators, flexible devices, and biological materials.

As one of the most prospective transitional metal oxide cathode materials for sodium-ion batteries (SIBs), P2-type Na2/3Ni1/3Mn2/3O2 layered oxide generally suffers from sluggish Na+ kinetics and complicated structural evolution. Here, a stable Co-free P2-Na2/3Li1/9Ni2/9Mn2/3O2 cathode material with multilayer oriented stacking nanoplates is reported, which exhibits high hydrostability realized by partial Li element substitution for Ni. A prominent rate capability (71.7% capacity retention at 5 C compared to 0.2 C), an excellent cycling stability (78.7% capacity retention at 2 C after 300 cycles) and a promoted performance even at a higher cutoff potential of 4.4 V were displayed owing to bifunctional strategy of chemical substitution coupled with structure modulation, and the as-synthesized material retains its original structure and electrochemical performance after being aged in water. Moreover, dominant Na+ capacitive storage mechanism, high thermostability and complete solid-solution reaction are explicitly elucidated through quantitative calculation of electrochemical kinetics and in-situ X-ray diffraction technique. These findings reveal the importance of rational chemical substitution and structure modulation strategy, and inspire novel design of high-performance cathode materials for rechargeable SIBs.

As a safe and sustainable cathode material for reversible Na-ion storage, the electrochemical performance of Na3.32Fe2.34(P2O7)2 with high operational safety can be enhanced via ion-doping engineering strategy. However, the rationale behind has remained unclear. In this study, we partially replace the Na+ and Fe2+ cations with K+ and Mg2+, respectively, where the K+ and Mg2+ dopants serve as pillars to support the crystallographic framework and thus reduce potential hysteresis. It is found that, compared to K doping at the Na site, Mg doping at the Fe site contributes to a more stable crystal structure and renders higher rate capability and cycling stability due to the inhibition of Fe migration and the reduction of structural disorder. The cation pillar strategy reported herein may shed light on enhancing cycling performance of other cathode materials for stable storage of not only Na ions but also other metals.

Due to the highest theoretical specific capacity of 4200 mA h g−1 for Li4.4Si, silicon(Si)-based materials could fulfill the increasing demands of high-energy lithium-ion batteries (LIBs). However, the intrinsic huge volume expansion during the lithiation/delithiation process results in rapid capacity decay and short cycle life and restricts the satisfactory electrical performance of Si-based anodes. Binder plays an important role of maintaining the contact integrity between active material, conductive additive and the current collector, thereby reducing the pulverization of the Si particles during charge/discharge. Here, the review systematically summarizes the synthesis methods, design principles and working mechanisms, including chemical composition, superstructure, and various interactions between different functional moieties of synthetic binders and natural biomass binders, to reveal the structure-composition-performance relationship, offer practical solutions to challenging problems associated with defects of Si-based electrode materials in LIBs and aim at exploiting new family of binders that could be used in industrial level as well as providing design principles for other electrode binders in rechargeable batteries.

The storage of renewable energy depends largely on sustainable technologies such as sodium-ion batteries with high safety, long lifespan, low cost, and non-toxicity. Pyrophosphate Na3.32Fe2.34(P2O7)2 cathode could meet this requirement, however, its structural stability needs to be further enhanced for practical purposes. To overcome this problem, Na-deficient Na3.32Fe2.11Ca0.23(P2O7)2 with exceptional stability is prepared by Ca selective doping in this work. In operando synchrotron-based X-ray diffraction (SXRD) and in situ X-ray absorption near edge spectroscopy (XANES) results reveal that the prepared Na3.32Fe2.11Ca0.23(P2O7)2 is a single-phase solid-solution reaction with high reversibility. A strong correlation between the voltage curve and lattice parameters is deciphered for the first time. Additionally, the atomic-doping-engineering strategy could significantly enhance the thermal and electrochemical stability of the electrode materials, contributing to their good structural reversibility and enhanced operational safety. Specifically, after 1000 cycles at 1 C, the Ca doped electrode achieves a high capacity retention of 81.7%, which is much better than that of the un-doped electrode (15.5%). Our work may pave a new avenue for designing safe and low-cost cathode materials for battery applications with long cycle life.

Layered manganese oxides cathodes of sodium-ion batteries show high energy density, but limited stability and rate capacity. Our previous studies have evidenced that layer-tunnel hybrid structure possesses both better rate performance and cyclic stability. Nevertheless, the complex phase transition is still ineluctable, leading to unsatisfying cycling performance. Be different from the previous study of ion-doping, this study demonstrates that the highly Na+-conductive Na2Ti6O13 coating can also effectually suppress the phase transition and improve the structure stability, air stability. Notably, the 3 wt % Na2Ti6O13 coated sample exhibits a primary capacity of 175.6 mA h g−1at 0.1 C between 2.0 and 4.1 V. And a capacity retention of 86.7% at 2C after 100 cycles. The Raman results show that the local lattice distortion around Mn3+ and Mn4+ ions is effectively suppressed. And the air stability also has been significantly improved. This study could provide a valid tactics into the surface modification of high-performance composite structure cathode materials for SIBs.

Polymer-ceramic composite electrolyte is an effective solution for developing high-performance and flexible all-solid-state lithium metal battery. However, the key bottleneck of composite electrolyte including low ionic conductivity and high interfacial impedance have impeded their industrialization in solid electrolyte lithium batteries. Here we present a polymer-ceramic hybrid electrolyte (polyethylene oxide (PEO)/polyvinylidene fluoride (PVDF)/Li6.4La3Zr1.4Ta0.6O12 (LLZTO)) is designed and modified by trace amount of liquid electrolyte. The addition of PVDF can not only reduce the crystallinity of PEO polymer, but also intensify the affinity between liquid electrolyte and the composite electrolyte. Furthermore, the interfacial modification can synchronously achieve the intimate connection, low interfacial impedance between the electrodes and solid electrolytes by forming the viscoelastic and stable layer. Due to the artful design, the solid-state battery deliver excellent performance. The Li symmetric cells show excellent interface stability without short circuits for 1000h. The assembled LiFePO4/Li cells exhibit a discharge capacity of 160.1 mA h g−1 after 200 cycles at 0.4C and 143.3 mA h g−1 at 5C. The composite solid electrolyte provides an effective and feasible methods to solve the interfacial issues and develop high performance solid lithium metal batteries.