To acquire an advanced anode material for sodium-ion batteries, in this study, the MoS2 nanosheet arrays are successfully in situ grown on hollow MXene sphere by hydrothermal method and subsequent heat treatment. The stacking of MXene is greatly limited by coating MXene on polystyrene (PS) sphere template. Further, MoS2 nanosheets are in situ grown on the MXene spheres through hydrothermal route, and the 3D hollow spherical MoS2@MXene material are obtained after heat treatment. The density functional theory calculations demonstrate that MoS2@MXene composite exhibits lower Na+ adsorption energy and smaller bandgap than pure MoS2. The resulting 3D hollow spherical MoS2@MXene material shows excellent cyclability and rate performance as an anode of the sodium-ion batteries, in which the specific capacities reach 354.8 mAh g(-1) after 1000 cycles at the current density of 1 A g(-1) (retention of 93.4 %), and 261.2 mAh g(-1) even at a high current density of 5 A g(-1). The high performance is attributed to the mitigation of self-aggregation of MoS2 nanosheets and the high electronic conductivity and fast transfer rate of sodium ions in the MoS2@MXene composite.

The construction of heterostructure materials has been demonstrated as the promising approach to design high-performance anode materials for sodium ion batteries (SIBs). Herein, micro-mesoporous cobalt phosphosulfide nanowires (Co3S4/CoP/NC) with Co3S4/CoP hetero-nanocrystals encapsulating into N-doped carbon frameworks were successfully synthesized via hydrothermal reaction and subsequent phosphosulfidation process. The obtained micro-mesoporous nanowires greatly improve the charge transport kinetics from the facilitation of the charge transport into the inner part of nanowire. When evaluated as SIBs anode material, the Co3S4/CoP/NC presents outstanding electrochemical performance and battery properties owing to the synergistic effect between Co3S4 and CoP nanocrystals and the conductive carbon frameworks. The electrode material delivers outstanding reversible rate capacity (722.33 mAh/g at 0.1 A/g) and excellent cycle stability with 522.22 mAh/g after 570 cycles at 5.0 A/g. Besides, the Ex-situ characterizations including XRD, XPS, and EIS further revealed and demonstrated the outstanding sodium ion storage mechanism of Co3S4/CoP/NC electrode. These findings pave a promising way for the development of novel metal phosphosulfide anodes with unexpected performance for SIBs and other alkali ion batteries.

The cathode material of the lithium-sulfur (Li-S) battery poses several challenges, including inadequate conductivity, the "shuttle effect", and volume expansion, all contributing to its reduced cycle lifespan. To address these issues, high-performance Li-S batteries can be manufactured by using transition metal selenide nanomaterials. These nanomaterials exhibit polarity, porosity, electrochemical catalytic activity, and high conductivity, making them well-suited hosts for sulfur cathodes. In this study, a metal-organic framework material was employed as a precursor to produce hollow dodecahedral transition metal selenides. This involved combining the precursor with selenium powder and subjecting it to high-temperature calcination. By leveraging bimetallic synergism and incorporating carbon nanotubes, the material's conductivity was improved, providing a conductive pathway for electron transport. The hollow ZnSe/CoSe2 structure's surface is interconnected by carbon nanotubes, forming a conductive network. This arrangement facilitates efficient sulfur utilization and prevents structural collapse during battery cycling. Moreover, ZnSe/CoSe2 enhances the chemical anchoring of polysulfide, promotes polysulfide transformation, and induces homogeneous nucleation of Li2S. Experimental results demonstrate excellent electrochemical performance when 50 mg of carbon nanotubes. At a rate of 0.05 C, the initial discharge specific capacity reaches 1225.75 mA h center dot g(-1), while at 1 C, it is 439.35 mA h center dot g(-1). After 200 cycles, the battery exhibits a capacity retention of 71.25% with a reversible capacity of 313.08 mA h center dot g(-1).

Using the electrodeposition approach, nanoflower nickel-cobalt bimetallic hydroxide (NiCoLDH) was synthesized in situ on nickel foam substrate as supercapacitor electrode material. The impacts of surfactant pretreatments on the morphology and electrochemical characteristics of LDH-based materials were examined. When poly(vinylpyrrolidone) (PVP) is applied as a pretreatment for NiCoLDH, it facilitates the formation of densely grown nanoflowers and a three-dimensional conductive network. This development significantly enhances the interaction between the electrode and the electrolyte, promoting an improved electrochemical performance. PVP adsorbed on the surface of nickel foam can further increase the loading of the electrode materials on nickel foam during the electrodeposition process. Consequently, NiCoLDH-PVP has a specific capacitance of 6.35 F cm(-2) at 1 mA cm(-2). The assembled NiCoLDH-PVP//AC asymmetric supercapacitor can reach an energy density of 741 mu Wh cm(-2) at a power density of 800 mu W cm(-2). The modification provides an approach and guides the simple and efficient synthesis of high-performance layered double hydroxides.

Lithium-rich layered Mn-based materials have attracted much attention because of their high specific capacity and high energy density, but they have the characteristics of irreversible capacity loss, low initial coulombic efficiency, and poor cycling performance. In this study, a core-shell structure, including Mn0.75Ni0.25C2O4 precursor as core and Li-rich Mn-based oxides (LRMO, Li1.2Mn0.54Ni0.13Co0.13O2) as shell layer respectively, was synthesized by co-precipitation and sol-gel method. After sintering at high temperatures, the element concentration-gradient oxides material (LRMO-G) was formed. The material was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) and its electrochemical performance was investigated by various electrochemical methods. The LRMO-G material exhibits a high initial discharge specific capacity of 268 mAh/g at 0.1 C, and extremely superior capacity retention (95.4 %) after 100 cycles at 1 C. The initial coulomb efficiency of the LRMO-G material increases to 85 %, which is 12 % higher than that of LRMO.

As the most promising anodes for Na+/K+ batteries (SIBs/PIBs), transitional metal sulfides present the advantages of high capacity, straightforwardly-controlled morphology and abundant redox reaction sites. However, maintaining the structural integrity of the electrode materials during cycling and improving the cycle life still face great challenges. Herein, CoS2@NPSC@MoS2 nano-spindle heterostructure with multiple heteroatoms co-doped carbon layers coupled with Janus metal sulfides (CoS2 and MoS2) were successfully fabricated via the successive organic coating, gas-phase phosphorization and the final hydrothermal reaction processes. Benefiting from the uniformly dispersed CoS2 nanocrystals in the interior of carbon layer and the MoS2 nanosheets arrays in the exterior, Na+/K+ diffusion distances are remarkedly shortened and the reaction kinetics are greatly improved, which also provide more active sites on the surface for exposure to the electrolyte. The presence of heterogeneous atomic N/P/S co-doped carbon layer greatly improves the electrochemical conductivity of the heterostructure and provide additional buffer space for volume changes, which is conducive to retaining the integrity of the electrode structure during the cycling processes. When used as the anode material for SIBs/PIBs, it reached the reversible specific capacity of 340.44 mAh g-1 at 5.0 A g-1 after 1000 cycles for SIBs and 37.53 mAh g-1 at 5.0 A g-1 after 800 cycles for PIBs. This work demonstrates a reliable and simple strategy for the rational design of Janus metal sulfides heterostructures for high performance Na+/K+ storage application.

Synthesis of advanced structure and multiple heteroatom-doped carbon based heterostructure materials are the key to the preparation of high-performance energy storage electrode materials. Herein, the hexapod-shaped Co1-xS@NPSC has been triumphantly prepared using hexapod ZIF-67 as the sacrificial template to prepare Co1-xS inner core and N, P, and S tri-doped carbon (NPSC) as the shell through the carbonization of the organic polymer precursor. When applied as anode for Na+ batteries (SIBs) and K+ batteries (PIBs), Co1-xS@NPSC presents the high reversible specific capability of 747.4 mAh/g at 1.0 A/g after 235 cycles and 387.8 mAh/g at 5.0 A/g after 760 cycles for SIBs, as well as 326.7 mAh/g at 1.0 A/g after 180 cycles for PIBs. The excellent storage capacity and rate capability of Co1-xS@NPSC is ascribed to hexapod structure of ZIF-67 unlike the common dodecahedron, which is constructed with interior porous and exterior framework repository, donating supplemental active sites, and doping of multiple heteroatoms forming organic polymer coating inhibiting the volume expansion and restrains the agglomeration of Co1-xS nanoparticles. This approach has paved a bright avenue to exploit promising anode materials with novel structure and hetero-atom doping for high-performance energy storage devices.

P2-type Fe-based oxides cathodes (Na0.67Fe0.5Mn0.35Co0.15O2, NFMC) have the disadvantage of a high air sensitivity and are prone to P2-O2 phase transition during charging to high voltage. In this work, an active coating layer of K2Na(Co(NO2)6) (KNC) is successfully coated on the surface of NFMC materials. The ex-situ X-ray diffraction patterns and the microstructure analysis of the KNC@NFMC show that no phase change occurs during charging/discharging in the range of 1.5-4.2 V. The electrochemical tests demonstrate that long-time stability of the active K2Na(Co(NO2)6) coating layer enhances the reversible reaction of Mn3+/Mn4+ and effectively suppresses the increase of charge transfer impedance during cycles. Compared to Na0.67Fe0.5Mn0.35Co0.15O2 oxide, the modified material has superior capacity retention of 89.7% for 200 cycles at 1 C (1 C=180 mAh/g) with a discharge specific capacity of 94.6 mAh/g.

Accurate battery remaining useful life (RUL) prediction plays an important role in ensuring reliable operation of electric vehicles. In this paper, a hybrid model based on Bayesian optimization of deep convolutional neural network and long short-term memory neural network (BO-DCNN-LSTM) is proposed for battery RUL prediction. Feature extraction of raw charging characteristic curves is performed by the multilayer CNN and preliminary capacity prediction is performed by the multilayer LSTM. The model performance is explored with different training, validation and testing strategies and different prediction starting points. Validation using NASA battery aging data shows that the mean absolute error (MAE) and root mean square error (RMSE) of the RUL prediction are 0.0139 Ah and 0.0195 Ah, respectively, when the prediction starting point is the 50th cycle. In addition, this paper visualizes the process of how the Bayesian optimization (BO) algorithm searches for the global optimal combinations in the high-dimensional hyperparameter space and discusses the impact of these hyperparameters on the prediction, filling the gap in this part of the research.

In this paper, a cobalt-based sulfide nanosheet structure (Co9S8/NC) was successfully synthesized by topochemical and phase transformation processes from a dodecahedral cobalt-based imidazole skeleton (ZIF-67) as a self-template. The 2D sheet structure facilitates full contact of electrode materials with the electrolyte and shortens the diffusion distance for electrons and ions. In addition, the nitrogen-doped carbon framework derived from ZIF-67 promotes electron transfer and provides a reliable skeleton to buffer volume expansion during discharging and charging. Finally, Co9S8/NC exhibits excellent rate capability and stable cycling performance for the anode of a sodium ion battery, delivering a specific capacity remaining at 530 mA h g-1 after 130 cycles at a current density of 1 A g-1.

2D-2D MXene@Co9S8/CoMo2S4 heterostructure has been successfully prepared by anchoring Co9S8/CoMo2S4 nanosheets on few-layered MXene through In-situ etching and ion exchange methods, as well as the subsequent sulfidation processes. MXene flakes used as substrate can effectively suppress the aggregation of Co9S8/CoMo2S4 nanosheets, which further increase reactive sites, ensure the full contact/infiltration of electrolyte, as well as promote charge transfer to improve the reversibility of redox reactions. Besides, this hierarchical structure of 2D -2D MXene@Co9S8/CoMo2S4 hybrids can provide buffer space for the volume expansion of electrode materials during the discharge/charge process. When applied as anode for SIBs, the hierarchical hybrids present superior electrochemical performances with outstanding rate capability (172 mAh/g at 5.0 A/g) and cycling stability (196 mAh/g at 1.0 A/g after 350 cycles), which were further demonstrated by the Ex-situ XRD and XPS results. This work provides an effective way to prepare heterostructure hybrid by combining MXene with binary metal sul-fides with unexpected performance in SIBs and may develop hybrid electrode materials for further application in commercial SIBs.

Machine learning can accurately predict the remaining useful life (RUL) of lithium-ion batteries because of its strong learning ability, efficient computing efficiency, and high accuracy. However, the prediction behavior and principle of many data-driven models as black box functions are unknown, and the potential of high accurate prediction requires further investigation. In view of these research gaps, this study proposes a novel hybrid model based on adaptive feature separable convolution (AFSC) and convolutional long short-term memory (ConvLSTM) network to improve the accuracy of RUL prediction and the interpretability of the model. The model extracts aging features from charging process data and can be applied to both early prediction and RUL prediction. Validation based on 124 commercial lithium iron phosphate battery aging data shows that the mean absolute error (MAE) of the early prediction results using the first 20 cycles is only 7 cycles, while the MAE of the RUL prediction is 0.12 cycles, both demonstrating excellent performance. In addition, the feature processing and prediction process of the model is analyzed through the visualization of upsampling and attention weights.

Reasonably combining the strengths of insertion and conversion anode materials to create an advanced anode material remains a formidable challenge for rechargeable lithium-ion batteries (LIBs). In this work, bulk MoS2 embedded with T-Nb2O5 nanospheres was synthesized via a simple hydrothermal process and a polydopamine carbon source was introduced by heat treatment. The design strategy can effectively accelerate the charge transfer and reduce the volume expansion during electrochemical cycling, leading to an improvement in lithium storage performance. As a consequence, the coexistence of T-Nb2O5, MoS2 and C can achieve the best synergistic effect when the molar ratio of Nb and Mo sources was 1 : 1. Notably, the T-Nb2O5@MoS2@C-1-1 electrode not only delivered an excellent reversible capacity of 518 mA h g(-1) at a current density of 0.1 A g(-1) but also exhibited superb cycling stability. The specific capacity of this electrode maintained 187 mA h g(-1) at 2 A g(-1) after 1000 cycles with a negligible capacity fading rate of only 0.015% per cycle.

Although LiNi0.8Co0.1Mn0.1O2 (NCM811) has been widely used in lithium-ion batteries (LIBs) as cathode materials, the high content of nickel typically leads to performance deterioration and other safety issues due to the catalytic decomposition of electrolyte. Herein, we propose a strategy to improve the stability of electrolyte by adopting anhydride-based additives with benzene group (e.g., 6FDA, FPA, and PSA). The theoretical calculation, electrochemical test, and structural characterization indicate that the addition of PSA enables NCM811 to better cycling performance at high, ambient, and low temperatures for pouch cells with SiO/graphite as the anode owing to its higher reduction potential in comparison with that of 6FDA and FPA.

The accordion-like Ti3C2 powder sample was obtained by preliminary etching of Ti3AlC2(MAX) with HF and different intercalation agents. It is shown that the intercalation agent of Na2SO4 is beneficial to increasing the layer spacing and specific area of Ti3C2, supplying more ion diffusion channels for the electrolyte, and full contact between the electrode materials and the electrolyte. The flower-like Ti3C2/LDH composites layered were synthesized with electrostatic self-assembly of positively charged Ni-Mn LDH nanosheets and negatively charged Ti3C2. The combination of Ni-Mn LDH and Ti3C2 realizes the microstructure modification, enhances the capacitance of the Ti3C2 and the cycling performance of LDH and decreases the internal resistance of LDH material. The specific capacitance of Ti3C2/LDH composite material is 82.3 mAh g−1 at a current density of 1 A g−1, and can maintain 34.3 mAh g−1 even at 10 A g−1. The specific capacitance remains at 84

Due to its high energy density and better safety performance, all-solid-state lithium batteries are regarded as important energy storage devices to replace the traditional liquid electrolyte Li-ion batteries. However, the problems of poor wettability of Li metal anode | solid-state electrolyte interface and easy growth of lithium dendrite have not been well solved. Here, we have constructed Fe-doped Li 7-3x Fe x La 3 Zr 2 O 12 (Fe-LLZO) and Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 (LLZTO) garnet-type double-layer solid electrolyte. The high density of Li 7-3x Fe x La 3 Zr 2 O 12 electrolyte and its interfacial wettability to Li metal not only effectively reduced the interface impedance between Li and solid electrolyte but also could stably cycle for more than 200 h without the growth of lithium dendrites at the rate of 0.1 mA cm −2 . In addition, the all-solid-state lithium battery (Li|Fe 0.1 -LLZO|LLZTO|LFP) with LiFePO 4 as a cathode also showed excellent cycle stability and C-rate performance.

Porous CoSe2 nanosheets are prepared on nickel foam by the hydrothermal method using Se powder as the selenium source and a zeolitic imidazolate framework (ZIF-67) as the template. The impact of hydrothermal temperature on the morphological structure and electrochemical performance of the CoSe2 materials is investigated by characterization with HRTEM, SEM, XRD, and so on, and CV and GCD electrochemical tests. The results show that the CoSe2-180 electrode material exhibits excellent electrochemical performance, and its unique nanosheet array structure can provide a highly active surface, large superficial area and fast ion transport channels. This is mainly attributed to the fact that the reaction at different hydrothermal temperatures can provide different nanosheet structures. An ordered array structure is most clearly observed at a hydrothermal temperature of 180 °C. In addition, the incorporated ZIF-67 backbone provides a pathway for rapid electron transfer and accommodates the volume expansion of the selenide during charge-discharge processes. Due to the distinct porous structure, the CoSe2-180 electrode shows a high specific capacity of 269.4 mA h g-1 at 1 A g-1 and a distinguished retention rate of 83.7% at 20 A g-1. After 5000 cycles, the specific capacity can be maintained at 83.4% of the initial value. Moreover, the asymmetric supercapacitor (ASC) device is assembled with CoSe2-180 as the positive electrode. It displays favorable electrochemical performance with the maximum specific energy of 45.6 W h kg-1 at a specific power of 800.8 W kg-1 and an original capacitance retention rate of 81.5% after 5000 cycles.

Through the hydrothermal method and the gas-phase phosphating method, the flower-like heterogeneous phosphorus-doped Co3S4@Ni3S4 was synthesized in situ on a nickel foam substrate as the binder-free electrode material for supercapacitors. Phosphorus-doped Co3S4@Ni3S4 electrode material combines the merits of transition metal sulfides and 3D porous network heterostructure, showing the excellent theoretical specific capacitance and the high specific surface area. The introduction of phosphorus atoms with an atomic radius larger than sulfur atoms can optimize the internal electronic structure and cause structural distortion. Therefore, the specific capacitance/specific capacity of this electrode can reach 3614 F g-1 (451 mAh g-1) at 1 A g-1 and still maintain the initial specific capacitance of 73% after 3000 cycles. The assembled P-Co3S4@Ni3S4-175//AC ASC device exhibits an ultra-high energy density of 72 Wh kg-1 at a power density of 800 W kg-1. Meanwhile, it can show extraordinary cyclic stability, with a retention rate of 91% after 5000 cycles. This work provides a feasible synthesis method to prepare the composite electrode materials for supercapacitors.

In order to improve the initial coulombic efficiency (ICE) and cycle performance of SiO, in this study, the disproportionation reaction of commercial SiO is performed with the assistance of Na2CO3 under high temperatures. A polydopamine-based carbon is then in situ formed on the surface of the mixture (d-SiO-G) of disproportionated-SiO and graphite. It is found that an appropriate amount of Na2CO3 can effectively enhance the ICE of the commercial SiO due to the formation of Si, SiO2, and silicate; the mass ratio of d-SiO-G to the dopamine monomer is the important factor in influencing the cycling stability of the d-SiO-G@C composite. Due to the synergistic effect of graphite and the polydopamine-based carbon layer, the ICE for the d-SiO-G@C composite is 72.6%, and its capacity retention reaches 86.2% after 300 cycles, which is 11% higher than that of d-SiO-G. The modification method is an effective strategy for SiO materials in commercial applications.

Carbonyl compounds are the most critical skeletons in organic synthesis owing to their ubiquitous and versatile reactivities. For instance, ketals and acetals may be employed as carbonyl-protecting groups, and several synthetic methods of preparing ketals and acetals have been reported in the recent decades. However, most of these transformations exhibit several limitations such as long reaction time, harsh reaction conditions, tedious workup procedures and unrecoverable catalyst, etc. Therefore, developing a novel metal-organic framework (MOFs)TiO2 as an efficient, recyclable photocatalyst for converting carbonyl compounds to acetals/ketals is critical. We demonstrate the efficient acetalisations of carbonyl compounds, enabling access to a wide variety of acyclic/ cyclic acetals, ketals or thioacetal by using various aromatic or aliphatic aldehydes/ketones under blue light. This strategy exhibits striking features, such as the use of abundant, sustainable alcohols as solvents and coupling agents, excellent yields, a recyclable photocatalyst and broad substrate scope. Therefore, this strategy may be applied in broadly green catalytic systems in industry.