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Na4MnV(PO4)3(NMVP) cathode materials have attracted significant attention as potential candidates for grid applications due to their distinctive structure and high theoretical capacity. However, their inadequate electronic conductivity compromises both cycling stability and rate capability, presenting a challenge for practical implementation. To address this issue, we employed a strategy involving Zr4+doping and dual-carbon coating to enhance the electrochemical performance of NMVP. The resulting Na3.8MnV0.8Zr0.2(PO4)3/C/rGO composite demonstrated markedly improved rate capability (71.9 mAh g−1at 60 °C) and sustained cyclic stability (84.8% retention at 2 C after 1000 cycles), as validated through comprehensive kinetics assessments. The enhanced performance can be attributed to the expanded Na-ion pathways facilitated by large size ion doping and the improved electronic conductivity enabled by the dual-layer coating.

Due to its abundant reserves, low cost, and wide global distribution, sodium is a promising resource for constructing low-cost and sustainable large-scale energy storage systems. The positive electrode is crucial in sodium-ion batteries, determining the energy density and cost of the entire device. Identifying cathode materials with high operating voltage, high reversible capacity, and good cycle stability remains a significant challenge for sodium-ion battery development. In this study, a novel synthesis process for layered Na0.44VOPO₄·1.6H₂O (NVOP) was proposed by oxidizing Na3V2(PO4)3(NVP) in aqueous solution. V3+in NVP was directly oxidized to a higher valence state using a simple one-step oxidation method. The electrochemical performance of this material as a cathode for sodium-ion batteries was thoroughly investigated. The prepared NVOP electrode exhibits a high average discharge potential of 3.4 V and a high reversible capacity of 126 mAh g−1at 0.05C, making it a promising candidate for high-energy sodium-ion batteries.

The soluble lithium polysulfides' shuttle effect impedes the practical application of Li–S batteries with high theoretical energy density. To confine the active S species in the cathode region, in this work, an artificial interlayer based on the composition of Ti2O(PO4)2(TOPO) and N-doped carbon nanotube (NCNT) is introduced to hinder the lithium polysulfides’ shuttle effect and enhance the reaction kinetics of active S species. The TOPO provides sufficient chemical bonding to soluble lithium polysulfides and fast Li+migration, while the NCNT ensures fast electron transport to the transformation of absorbed lithium polysulfides. Thanks to the synergistic combination of TOPO and NCNT, at 0.1 C, the initial discharge specific capacity of corresponding Li–S batteries is 1483.55 mAh g−1, while at 1 C, a capacity decay of 0.14 % per cycle is achieved for 400 cycles.

As an ideal photocatalyst in the photoelectrochemical (PEC) water oxidation area, hematite (α-Fe2O3) has received much attention from scientists on account of its favorable band gap and excellent stability in alkaline media. However, the practical photocurrent yield of α-Fe2O3is much less than the theoretical value because of the high charge recombination and the low charge transport. Herein, a novel ferroelectric Fe2O3/Pb(Zr0.2Ti0.8)O3photoanode (Fe2O3/PZT) was fabricated by simple spin coating along with a one-step calcination method for the first time. As expected, the Fe2O3/PZT photoanode showed a significantly greater photocurrent (by ∼10 times) and the initial potential (by ∼100 mV) was more negative than that of the pure Fe2O3nanorod photoanode, which was attributed to the depletion layer width increase and the upward band bending in Fe2O3induced by ferroelectric polarization of PZT, leading to efficient charge separation and injection. Moreover, the photoelectrochemical performance of the Fe2O3/PZT nanorod photoanode could be regulated by simply changing the polarization direction of PZT. In addition, the Fe2O3/PZT nanorod photoanode showed not only a fast and repetitive light response but also long-term stability for 96 h. This research presents a novel route to enhance the efficiency of charge separation and affords theoretical guidance for preparing the high-efficiency PEC photoanodes and the switchable control of the photoelectrochemical response.

A two-dimensional (2D)/three-dimensional (3D) hybrid heterostructure has recently emerged as an effective method for improving photocatalytic efficiency. In this work, we perform a comprehensive first-principles study of the structural, electronic, and optical properties of a novel 3D-SiC/2D-MoS2heterostructure. The calculation results reveal that the SiC(0001) surface/MoS2monolayer-integrated heterostructure in Schottky contact with a new chemical bonding contributed to the surface adhesion and optoelectronic properties. Meanwhile, the valence and conduction band-edge positions of SiC and MoS2changed with the Fermi level and formed a desired type-II band alignment, which greatly facilitate the rapid separation of photogenerated carriers. Moreover, the surface state of SiC(0001) can be removed when combined with MoS2, and their band gap is also reduced. Furthermore, Bader charge and charge density difference indicated that there is a remarkable separated distribution of electrons and holes at the interface. These results demonstrated that the band structure of the 3D-SiC/2D-MoS2heterostructure had significant advantages to improve the photocatalytic efficiency under visible-light irradiation.

Although the Li metal anode has a high theoretical capacity and low potential, the uncontrolled growth of Li dendrites and the significant volume variation of the Li anode prevent the practical deployment of lithium metal batteries (LMBs). To effectively control the Li dendrite growth with suppression, in this contribution, the Ni(OH)2nanosheets modified Prussian blue tubes (PBT/Ni(OH)2) are employed to construct a three-dimensional framework (3D) on the surface of Li. The PBT can homogenize the Li+flux, while the Ni(OH)2nanosheets provide sufficient space to accommodate the volume change of Li. Thus, the growth of Li dendrites is largely suppressed compared to pristine Li. In detail, with the introduction of PBT/Ni(OH)2, the Li||Li cells provide 500 h of consistent cycling performance at 1 mA cm−2, while the Li||Li4Ti5O12(LTO) cells also exhibit superior cycle reversibility over 450 cycles at 175 mAh g−1.

NASICON-typed Na3V2(PO4)3is considered the most promising cathode material for sodium-ion batteries. However, it still exhibits a limitation in terms of energy density. Herein, Mn/Si-codoped Na3.5+xV1.5Mn0.5(PO4)3–x(SiO4)xwas synthesized to increase reversible capacity and operating voltage. The effects of co-substitution on structural stability and electrochemical performance are investigated. Among various doping concentrations, the optimized Na3.55Mn0.5V1.5(PO4)2.95(SiO4)0.05shows remarkably improved cyclability and reversibility. It delivers a reversible capacity of 116 mAh g–1at 0.2C, good cycling stability (capacity retention of 80.2% after 200 cycles), and an outstanding rate capacity of 92 mAh g–1at 10C.

The inhomogeneous lithium metal (Li) deposition and low lithium ion (Li+) mobility lead to the formation and growth of Li dendrites, which impede the desirable performance of Li metal batteries (LMBs) with high energy density in widely practical applications. Herein, a high-entropy MnCoNiCuZn-Prussian blue analogue (HE-PBA) is utilized to modify the commercial polypropylene separator (PP@HE-PBA), which will form an artificial protective layer on the surface of Li. The polar –CN groups of HE-PBA can enhance the wettability of PP to the electrolyte, while the movement of PF6−anions are flexibly tuned by the appropriate absorption ability and synergistic effect of multiple metal ions in HE-PBA. A high Li+transference number of 0.69 is achieved, which can relieve the Li+concentration polarization, regulate the Li+flow, and realize the uniform Li deposition. With PP@HE-PBA, the Li||Li symmetric cells display durability up to 600 h in the ester-based electrolyte at 1 mA cm−2for 1 mAh cm−2. Also, the PP@HE-PBA exhibits great potential in LMBs, where the Li4Ti5O12(LTO) ||Li and sulfated polyacrylonitrile (S-PAN) ||Li batteries deliver superior cycling performance to those without PP@HE-PBA.

The LiS batteries have great potential in energy storage because of their high theoretical capacity and energy density, low cost and environmental friendliness. However, the practical application of LiS batteries is hindered by their undesirable electrochemical performance caused by the shuttling effect of soluble lithium polysulfides and sluggish redox kinetics, which needs an efficient immobilizer to achieve fast capture and conversion of lithium polysulfides. This work prepared the heterogeneous MnO/MnS with O/S vacancies (MnO-OV/MnS-SV) by a universal approach combining sol-gel and calcination under a reductive atmosphere with MnSO4·H2O precursor. With the synergistic effect between strong adsorption of MnO-OVand effective catalysis of MnS-SVto lithium polysulfides, the as-prepared MnO-OV/MnS-SVpowders with high yield (~45 %) are potential candidates to modify commercial polyethylene (PE) separator for large scale application of LiS batteries. As expected, the LiS batteries with MnO-OV/MnS-SVmodified PE delivers a specific discharge capacity of 1248.09 mAh g−1at 0.1C and maintains 721.92 mAh g−1when the rate increases to 2C. At 1C, the initial discharge specific capacity is 986.14 mAh g−1, which can operate for 400 cycles with a decay rate of 0.23 % per cycle. Even At a relatively higher S mass loading of 3.5 mg cm−2, the LiS battery with the assistance of MnO-OV/MnS-SVshows a discharge capacity of 658.3 mAh g−1after 50 cycles.

Germanium based sulfides are potentially attractive as anode material for sodium ion batteries but rarely investigated. Herein, we firstly investigated Na+storage properties of pristine Cu2GeS3(PCGS) and found an effective strategy to improve its performance by a single lithiation/delithiation cycle obtaining ultrafine nanoparticle copper germanium sulfide (NCGS). The lithiation/delithiation process leads to the formation of a stable Li-containing solid electrolyte interphase film and a significant improvement of sodiation kinetics. Therefore, the NCGS anode delivers favorable capacity retention and better rate capability compared with that of a PCGS whether in the half cell or in the full cell, showing great promise for energy storage application. 锗基硫化物作为钠离子电池负极具有潜在的吸引力, 但相关报道甚少. 为此, 我们研究了Cu2GeS3(PCGS)的储钠性能, 发现通过单次 嵌锂/脱锂循环获得超细纳米微粒铜锗硫(NCGS)是一种改善其储钠性能的有效策略. 嵌锂/脱锂过程能够在材料表面形成一层稳定的含锂 固态电解质相界面膜, 并提高材料的嵌钠动力学. 因此, 与PCGS相比, NCGS在半电池和全电池中都显示出良好的循环性能和倍率性能, 在 能源存储领域具有广阔的应用前景.

Development of cheap, abundant and noble-metal-free materials as high efficient oxygen reduction electrocatalysts is crucial for future energy storage system. Here, one-dimensional (1D) MnO N-doped carbon nanofibers (MnO-NCNFs) were successfully developed by electrospinning combined with high temperature pyrolysis. The MnO-NCNFs exhibit promising electrochemical performance, methanol tolerance, and durability in alkaline medium. The outstanding electrocatalytic activity is mainly attributed to several issues. First of all, the uniform 1D fiber structure and the conductive network could facilitate the electron transport. Besides, the introduction of Mn into the precursor can catalyze the transformation of amorphous carbon to graphite carbon, while the improved graphitization means better conductivity, beneficial for the enhancement of catalytic activity for oxygen reduction reaction (ORR). Furthermore, the porous structure and high surface area can effectively decrease the mass transport resistance and increase the exposed ORR active sites, thus improve utilization efficiency and raise the quantity of exposed ORR active sites. The synergistic effect of MnO and NCNFs matrix, which enhances charge transfer, adsorbent transport, and delivers efficiency in the electrolyte solution, ensures the high ORR performance of MnO-NCNFs. 廉价、 储量丰富的非贵金属材料作为高效氧还原电催化剂是未来能量存储系统实际应用的关键. 基于此, 我们通过静电纺丝法并结合相应热处理制备了一维氮掺杂碳纳米纤维包覆一氧化锰(MnO-NCNFs). 该材料在碱性体系中表现出良好的电化学性能, 耐甲醇腐蚀性和稳定性. 其优异的电催化活性主要归结于以下几点: (1) 均一的一维纤维结构和导电网络能够促进反应过程中快速的电子转移; (2) 过渡金属锰的引入能够促进无定型碳向石墨碳的转变, 同时石墨化程度的提高意味着更好的导电性, 有利于氧还原活性的提高; (3) 多孔结构和高比表面积能够有效降低传质阻力并提高暴露的氧还原活性位点数量, 进而提高物质利用效率.

The considerably theoretical electrochemical performance makes NiCo(HPO4)2·3H2O a potential electrode material for hybrid supercapacitor (HSC). Nevertheless, its practical application is impeded by the limited preparation process and undesirable structure, causing its incomplete utilization and unsatisfactory electrochemical performance. Herein, we rationally design a freestanding HSC electrode based on NiCo(HPO4)2·3H2O with the inner boundary to achieve its high utilization. The construction of an inner boundary can increase the ion transport channels and active sites during electrochemical processes. The freestanding NiCo(HPO4)2·3H2O-based electrode in three-electrode system delivers high specific capacitance (3005.1 mF cm−2at 1 mV s−1) and favorable rate capability (2795 mF cm−2at 10 mV s−1). When evaluated as a cathode and matched with the activated carbon anode, the asymmetrical HSC exhibits a specific capacitance of 2547.3 mF cm−2(10 mV s−1) and desirable cycling stability after 4000 cycles (87 % capacitance retention).

Lithium (Li) metal, with extremely high specific capacity and low reduction potential, is considered one of the most promising anode candidates for next-generation batteries. However, uncontrolled growth of dendritic Li and extreme volume fluctuation during cycles hinder the broad application of Li metal anodes. Herein, Li dendrite growth can be effectively suppressed by constructing a unique hierarchical porous structure. ~300 nm rigid carbon nano-box contains abundant ~20 nm Cu3P/CoP heterostructural nanobubbles. Densely growth villiform carbon tubes tangled with ~50 µm carbon nanotubes cover the surface of the carbon nano-box. This flexible interlaced matrix (Cu3P/CoP@C/CNT) possessing 3D hierarchical porous interspace and structure can effectively confine metallic Li. More than physical confinement, strong chemical bonding between Cu3P/CoP heterostructures and Li atoms is also proved by DFT calculation to regulate Li plating behavior. The LiǀCu3P/CoP@C/CNT composite anode exhibits a high average efficiency of 94.6% over 220 cycles and a long-running lifespan for 400 h with an exceptionally low voltage hysteresis of 24 mV. LiFePO4|Li@Cu3P/CoP@C/CNT full cells can be cycled 300 times at a negligible capacity decay of 0.01% per cycle at 1 C. This work inspires a self-supporting and hollow heterostructured Li container design, promoting the development of Li metal host anodes.

NixCo2x(OH)6x, as a precursor of intensively studied NiCo2O4, has been directly deposited into self-standing titanium nitride nanotube array (TiN NTA) grid monolithic supports to form a coaxial nanostructured electrode for supercapacitors. With TiN NTA substrates providing a large surface area, fast electron transport, and enhanced structure stability, this NixCo2x(OH)6x/TiN electrode exhibits superior pseudocapacitive performance with a high specific capacitance of 2543 F g–1at 5 mV s–1, remarkable rate performance of 660 F g–1even at 500 mV s–1, and promising cycle performance (about 6.25% capacitance loss for 5000 cycles). Interestingly, the NixCo2x(OH)6x/TiN NTA electrode outperforms the NiCo2O4/TiN NTA electrode, indicating that this self-standing NixCo2x(OH)6x/TiN NTA monolith is a promising candidate for high-performance supercapacitor applications.

In this study, titanium nitride-vanadium nitride fibers of core–shell structures were prepared by the coaxial electrospinning, and subsequently annealed in the ammonia for supercapacitor applications. These core–shell (TiN-VN) fibers incorporated mesoporous structure into high electronic conducting transition nitride hybrids, which combined higher specific capacitance of VN and better rate capability of TiN. These hybrids exhibited higher specific capacitance (2 mV s–1, 247.5 F g–1) and better rate capability (50 mV s–1, 160.8 F g–1), which promise a good candidate for high-performance supercapacitors. It was also revealed by electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) characterization that the minor capacitance fade originated from the surface oxidation of VN and TiN.

ZnSe, as a promising electrode material for sodium storage, has a high theoretical capacity, low cost, and excellent physicochemical properties. The poor reaction kinetics and huge volume variation of ZnSe hinder its practical applications. Therefore, in this study, ZnSe electrode materials embedded in carbon nanofibers (ZnSe@NC@NCNFs) were synthesized through electrospinning and selenization using a Zn-based metal-organic framework (Zn-MOF) precursor. During the calcination process, the MOF-derived porous N-doped carbon layer wraps the ZnSe nanoparticles, and the one-dimensional (1D) carbon nanofiber forms a second N-doped carbon protective layer. The interwoven nanofibers can be severed as a freestanding electrode for sodium storage without conductive and binder agents. In situ X-ray diffraction (XRD) demonstrates the formation of irreversible NaZn13during the initial discharge process, which can act as sodiophilic sites and buffering matrices for subsequent Na+insertion/extraction. The ZnSe@NC@NCNFs exhibit significant electrochemical performance for sodium storage with high reversible capacity and desired rate performance.

The insulating properties of S/Li2S2/Li2S and the soluble Li2S4/Li2S6/Li2S8obstruct the practical application of Li-S batteries. In this work, highly ordered N and S co-doped mesoporous carbon tubes (NSMCTBs) with high specific surface areas and large pore volume are employed to confine and improve the utilization efficiency of S species in Li-S batteries. The strong SnLi2...N interaction and S-S chemical bond between thiophenic S and Li2Snguarantee the exceptional electrochemical performance of as-prepared NSMCTBs/S cathode. A relatively high discharge capacity of 1315.2 mAh g−1is achieved for the first cycle at 0.5 C and maintained at 644.1 mAh g−1after 500 cycles. The NSMCTBs/S with high S content of up to 80%, it also delivers a discharge capacity of 1092.1 mAh g−1and considerable cycling performance. More importantly, the NSMCTBs/S can effectively suppress the self-discharge behavior of Li-S batteries.

Copper tin sulfides (CTSs) have widely been investigated as electrode materials for supercapacitors owing to their high theoretical pseudocapacitances. However, the poor intrinsic conductivity and volume change during redox reactions hindered their electrochemical performances and broad applications. In this study, carbon quantum dots (CQDs) were employed to modify CTSs. The structures and morphologies of obtained materials were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD revealed CTSs were composed of Cu2SnS3 and Cu4SnS4, and TEM suggested the decoration of CQDs on the surface of CTSs. With the decoration of CQDs, CTSs@CQDs showed a remarkable specific capacitance of 856 F·g−1 at 2 mV·s−1 and a high rate capability of 474 F·g−1 at 50 mV·s−1, which were superior to those of CTSs (851 F·g−1 at 2 mV·s−1 and 192 F·g−1 at 50 mV·s−1, respectively). This was mainly ascribed to incorporation of carbon quantum dots, which improved the electrical conductivity and alleviated volume change of CTSs during charge/discharge processes.