Efficient Ion Transport Research Articles

Preparation of highly conductive anion exchange membranes by introducing dibenzothiophene monomer into the polymer backbone

The poly(aryl piperidinium) backbone has outstanding electrical conductivity and chemical stability, which is ideal for the preparation of anion exchange membranes (AEMs). Hence, in this research we prepared a series of high performance AEMs by introducing electron-rich dibenzothiophene (DBT) monomer into poly(aryl piperidinium) polymer backbone. The larger conjugated surface of the DBT monomer and the presence of heteroatoms facilitated intermolecular interactions between the polymers, which induced the generation of highly efficient ion-transport channels within the membranes, as evidenced by atomic force microscopy (AFM) images. The highest molar addition of DBT monomer, QPDBTTP-25 membrane, showed the highest conductivity (190.90 mS cm−1 at 80 °C) while maintaining robust dimensional stability (swelling ratio was 23.66 % at 80 °C). Owing to the advantages of the poly(aryl piperidinium) polymer backbone, the QPDBTTP-25 membrane also exhibited excellent mechanical properties (tensile strength of 53.03 MPa under fully hydrated condition) and durable chemical stability (conductivity retention remained at 93.2% after being immersed in 2 M NaOH solution at 80 °C for 1500 h). The H2/O2 fuel cell test based on QPDBTTP-25 membrane resulted in a peak power density of 384 mW cm−2 at 80 °C.

A three-dimensional co-continuous network structure polymer electrolyte with efficient ion transport channels enabling ultralong-life all solid-state lithium metal batteries

Solid polymer electrolytes (SPEs) have emerged as one of the most promising candidates for the construction of solid-state lithium batteries due to their excellent flexibility, scalability, and interface compatibility with electrodes. Herein, a novel all-solid polymer electrolyte (PPLCE) was fabricated by the copolymer network of liquid crystalline monomers and poly(ethylene glycol) dimethacrylate (PEGDMA) acts as a structural frame, combined with poly(ethylene glycol) diglycidyl ether short chain interspersed serving as mobile ion transport entities. The preparaed PPLCEs exhibit excellent mechanical property and outstanding electrochemical performances, which is attributed to their unique three-dimensional co-continuous structure, characterized by a cross-linked semi-interpenetrating network and an ionic liquid phase, resulting in a distinctive nanostructure with short-range order and long-range disorder. Remarkably, the addition of PEGDMA is proved to be critical to the comprehensive performance of the PPLCEs, which effectively modulates the microscopic morphology of polymer networks and improves the mechanical properties as well as cycling stability of the solid electrolyte. When used in a lithium-ion symmetrical battery configuration, the 6 wt%-PPLCE exhibites super stability, sustaining operation for over 2000 h at 30 °C, with minimal and consistent overpotential of 50 mV. The resulting Li|PPLCE|LFP solid-state battery demonstrates high discharge specific capacities of 160.9 and 120.1 mA h g−1 at current densities of 0.2 and 1 C, respectively. Even after more than 300 cycles at a current density of 0.2 C, it retaines an impressive 73.5% capacity. Moreover, it displayes stable cycling for over 180 cycles at a high current density of 0.5 C. The super cycle stability may promote the application for ultralong-life all solid-state lithium metal batteries.

Facilitated belt for ion transport by comb-shape Poly(terphenyl piperidone) carried with macrocyclic crown ether as anchor in anion exchange membrane

To ensure efficient ion transport in anion exchange membranes (AEMs) for hydrogen production, it is essential to develop efficient ion transport pathways. Utilization of intermolecular interactions induced by embedded macrocycles is an attemptable approach. Self-aggregated channels can be constructed with this force serving as a driving force for stepped-up ion transport. Herein, we present a delicate strategy to polymerize the macro crown ether in the backbone and graft flexible alkyl long chains to prepare comb-type copolymers as AEMs. The macrocycle dynamically traps ammonium ions as an anchor which accelerates the aggregation of ionic phases. The resulting AEMs show favorable membrane-forming ability and tensile strength. As the side chain length increases, the microphase-separated morphology develops well and formed ‘belt’-like channels in the poly(terphenyl piperidone)-5-bis-quaternary ammonium (PTCP-5-bisQA) membrane, exhibiting a hydroxide conductivity of 78.1 mS/cm at 80 °C. The alkaline durability of PTCP-5-bisQA AEM is explored by nuclear magnetic hydrogen spectrum (1H NMR) investigation at 80 °C for 720 h. Furthermore, the PTCP-5-bisQA based electrolyzer reaches a current density of 330 mA/cm2 at 1.85V by 1 wt% potassium hydroxide solution circulation. A life endurance observation is carried out on this electrolyzer for a 100h operation with performance degradation rate of 40.1 mV/h.

Ultrasensitive electrochemical sensing platform based on Zr-based MOF embellished single-wall carbon nanotube networks for trace analysis of methyl parathion

In this work, a novel electrochemical sensor was designed based on Zr-based metal–organic framework (UIO-66) nanoparticles embellished single-wall carbon nanotube networks (SCN) for the detection of methyl parathion (MP). The synergistic combination of SCN and UIO-66 nanoparticles could fully exert each advantage to boost the MP electrochemical sensing analysis performance. SCN with one-dimensional hollow nanostructures formed three-dimensional interconnected carbon conductive networks, which possessed excellent conductive properties and acceptable specific surface area, enabling efficient transport of electrons and ions. UIO-66 nanoparticles with Zr-OH groups contributes and porous structure to the good affinity for phosphate groups on MP molecules, which enhanced the selective recognition and enrichment capability of sensing electrode towards MP. Under the multifunctional integration of SCN and UIO-66 nanoparticles, the SCN@UIO-66/GCE sensor could present satisfactory MP electrochemical detection performance (LOD: 8.05 nM, linear MP concentration range: 0.01–10 μM). The satisfactory practical property was realized at the SCN@UIO-66/GCE sensor with satisfactory recovery rates of 98.28–101.95 % and low RSD of 1.23–3.01 % for the electrochemical detection of MP in orange juice and lettuce samples.

Building Stable Solid-State Potassium Metal Batteries.

Solid-state potassium metal batteries (SPMBs) are promising candidates for the next generation of energy storage systems for their low cost, safety, and high energy density. However, full SPMBs are not yet reported due to the K dendrites, interfacial incompatibility, and limited availability of suitable solid-state electrolytes. Here, stable SPMBs using a new iodinated solid polymer electrolyte (ISPE) are presented. The functional ions reconstruct ion transport channels, providing efficient potassium ion transport. ISPE shows a combination of high ionic conductivity, superior interfacial compatibility, and electrochemical stability. In situ alloying and iodinated interlayer increase K metal compatibility for prolonged cycling with low polarization. Moreover, the ISPE enables SPMBs with Prussian blue cathode stable operation at a high voltage of 4.5V, a superior rate capability, and long-term cycling over 3000 cycles (4.2V vs K+/K) with an ultra-high coulombic efficiency of 99.94%. More importantly, a classic solid-state potassium metal pouch cell achieves 4.2V stable cycling over 800 cycles with a high retention of 93.6%, presenting a new development strategy for secure and high-performance rechargeable solid-state potassium metal batteries.

Catalytic chemistry inspired hollow carbon nanofibers loaded with NiS/Ni as high-performance and safe Li+ reservoir

Transition metal sulfides (TMSs) based anodes hold a very broad application prospect in lithium ion batteries (LIBs). In this work, the catalytic effect of metallic nickel at high temperature was used to generate hollow carbon nanofibers loaded with NiS and Ni (denoted as NiS/Ni@HCNF). The heteroatoms doped carbon fibers buffer the huge volumetric change of NiS during the discharge/charge process, and enhance the ion transport efficiency and electrical conductivity. In addition, the high specific surface area brought by the hollow carbon nanofibers can accelerate the electrolyte penetration and speed up the transport of ions as well as electrons. When used as anode of half cell, this electrode gives 958.5 and 612.9 mAh/g after running 1000 cycles under 1 and 2 A/g, showing the extremely-low attenuation rates of 0.0483 % per cycle and 0.0643 % per cycle, respectively. Impressively, NCM//NiS/Ni@HCNF battery shows the discharge capacity of 187.6 mAh/g at 1st cycle. Regarding the next 100 cycles, the relatively-high discharge capacities (>110 mAh/g) and coulombic efficiency (CE) values (>96 %) are discerned. It is noted that the usage of NiS/Ni@HCNF electrode improves the activation energy for thermal runaway, corroborating the elevated thermal safety of battery.

Nonsolvent-induced electrospun fibers with crater-like surface and high-loading polytriphenylamine-derived as a flexible cathode for lithium-ion batteries

Fabricating electrodes simultaneously possessing remarkable flexibility, excellent mechanical properties, and high energy density remains a significant challenge in flexible lithium-ion batteries (LIBs). Herein, a series of flexible organic composite films were prepared with high-loading polytriphenylamine (PTPA) and the derivative (PTPA-PO) as active material, along with carbon nanotubes (CNTs) serving as conductive filler. The fabrication employed the polyethylene oxide (PEO) assisted nonsolvent (or poor solvent) induced phase separation electrospinning (NIPSE) method. Subsequently, the fiber morphology and electrochemical applications of the flexible organic composite films were systematically studied. Notably, the 60 % PTPA-PO/20 % CNTs/PEO flexible electrode with a high-loading active material of 60 wt% exhibits a significant discharge capacity of 146.6 mAh·g−1 and a favorable discharge platform ∼ 3.7 V vs. Li. Furthermore, the inherent flexibility of electrode contributes to efficient and stable transport of ions and electrons, resulting in a fine capacity retention of 93.3 % after 100 cycles. The improvement of electrochemical performance can be rationalized by the unique internal conductive network and crater-like surface structure of the fibers formed through the NIPSE method. This work provides an efficient method to fundamentally improve the energy storage performance and flexibility of LIBs.

High mechanical strength Si anode synthesis with interlayer bonded expanded graphite structure for lithium-ion batteries

Despite advancements in silicon-based anodes for high-capacity lithium-ion batteries, their widespread commercial adoption is still hindered by significant volume expansion during cycling, especially at high active mass loadings crucial for practical use. The root of these challenges lies in the mechanical instability of the material, which subsequently leads to the structural failure of the electrode. Here, we present a novel synthesis of a composite combining expanded graphite and silicon nanoparticles. This composite features a unique interlayer-bonded graphite structure, achieved through the application of a modified spark plasma sintering method. Notably, this innovative structure not only facilitates efficient ion and electron transport but also provides exceptional mechanical strength (Vickers hardness: up to 658 MPa, Young’s modulus: 11.6 GPa). This strength effectively accommodates silicon expansion, resulting in an impressive areal capacity of 2.9 mA h cm−2 (736 mA h g−1) and a steady cycle life (93% after 100 cycles). Such outstanding performance is paired with features appropriate for large-scale industrial production of silicon batteries, such as active mass loading of at least 3.9 mg cm−2, a high-tap density electrode material of 1.68 g cm−3 (secondary clusters: 1.12 g cm−3), and a production yield of up to 1 kg per day.

Synthesis of flower-type nanorods with Zn-doped manganese vanadate (Mn(VO3)2) and carbon nanofibers (CNFs) for enhanced performance in battery-type supercapacitors

Among the various novel electrode materials prepared to enhance the electrochemical performance of supercapacitors, ordered nanoarray structures stand out as highly promising candidates for use as binder-free electrodes. In this study, flower type nanorods of zinc manganese vanadate (MnZn3(VO4)2) grown on 3-D nickel foam, with additional incorporation of Carbon nanofibers (CNFs)(MZVC) by using a one-step hydrothermal method. The nanostructured MZVC electrode exhibited a specific capacitance of 469 Fg−1 at a current density of 0.5 Ag−1, surpassing the specific capacitance values of the pristine electrodes (ZV-304 Fg−1, MV-263 Fg−1) and MZV − 333 Fg−1) at the same current density. Remarkably, the MZVC composite electrode exhibited an exceptional retention rate of approximately 82.6 % even after 5000 charge–discharge cycles. All of the fabricated electrodes underwent comprehensive characterization utilizing different analytical techniques to assess their structural, and surface morphological attributes. Further, Electrochemical behavior was assessed for ZV, MV, MZV, and MZVC nanostructures through cyclic voltammetry (CV), galvanostatic charge /discharge (GCD), and electrochemical impedance spectroscopy (EIS). This 3D porous flower-type electrode structure offers an abundance of active sites for electrochemical reactions, enables efficient electron and ion transport, and mitigates the aggregation of MZVC flower structures throughout prolonged cycling.

Formulation of Hierarchical Nanowire-Structured CoNiO2 and MoS2/CoNiO2 Hybrid Composite Electrodes for Supercapacitor Applications.

Hierarchical porous nanowire-like MoS2/CoNiO2 nanohybrids were synthesized via the hydrothermal process. CoNiO2 nanowires were selected due to the edge site, high surface/volume ratio, and superior electrochemical characteristics as the porous backbone for decoration of layered MoS2 nanoflakes to construct innovative structure hierarchical three-dimensional (3D) porous NWs MoS2/CoNiO2 hybrids with excellent charge accumulation and efficient ion transport capabilities. Physicochemical analyses were conducted on the developed hybrid composite, revealing conclusive evidence that the CoNiO2 nanowires have been securely anchored onto the surface of the MoS2 nanoflake array. The electrochemical results strongly proved the benefit of the hierarchical 3D porous MoS2/CoNiO2 hybrid structure for the charge storage kinetics. The synergistic characteristics arising from the MoS2/CoNiO2 composite yielded a notably high specific capacitance of 1340 F/g at a current density of 0.5 A/g. Furthermore, the material exhibited sustained cycling stability, retaining 95.6% of its initial capacitance after 10 000 long cycles. The asymmetric device comprising porous MoS2/CoNiO2//activated carbon encompassed outstanding energy density (93.02 Wh/kg at 0.85 kW/kg) and cycling stability (94.1% capacitance retention after 10 000 cycles). Additionally, the successful illumination of light-emitting diodes underscores the significant potential of the synthesized MoS2/CoNiO2 (2D/1D) hybrid for practical high-energy storage applications.

Derivation of porous cellulose propionate using hydrated hydroxyl groups and hydraulic pressure

This study aimed to enhance the thermal stability of microporous separators by introducing cellulose propionate (CP) as an innovative polymer matrix material, supplemented with glycerin as an additive. CP/glycerin composite membranes were created using hydraulic pressure techniques to reinforce essential separator properties. SEM analysis unveiled interconnected pores crucial for efficient ion transport, initiating water flux measurements at 5 bar. These measurements showcased improved mechanical strength, resulting in a porosity of 74.1 %. FT-IR spectroscopy illustrated CP-glycerin interactions, inducing plasticization and facilitating pore formation. Thermal Gravimetric Analysis (TGA) demonstrated superior thermal stability in CP/glycerin composite membranes compared to cellulose acetate (CA). Differential Scanning Calorimetry (DSC) revealed a slight reduction in thermal stability within a specific temperature range due to glycerin-induced plasticization effects. Nonetheless, the melting temperature (Tm) of CP/glycerin membranes increased to 188.4 °C, indicating heightened stability at elevated temperatures. Despite pressure-induced pore formation, CP/glycerin membranes exhibited enhanced thermal stability, suggesting reinforced molecular interactions. Overall, this study introduces a novel CP/glycerin composite membrane featuring improved thermal stability, enhanced strength, and controlled pore structures essential for efficient lithium-ion battery applications.

Three Ways to (Pseudo)cubic Structure Models: Phase Transition and Pseudosymmetry in Orthorhombic Cs3MO4 (M = V, Nb, or Ta).

The new oxometalates Cs3NbO4 and Cs3TaO4 together with Cs3VO4 crystallize with the K3NO4 structure type [Pnma, a = 12.495(2) Å, b = 9.0183(14) Å, and c = 6.6529(10) Å for the V compound; a = 12.928(2) Å, b = 9.177(3) Å, and c = 6.739(4) Å for the Nb; and a = 12.963(4) Å, b = 9.122(2) Å, and c = 6.774(1) Å for the Ta compound]. Their crystal structures were evaluated on the basis of single-crystal and powder X-ray diffractometry, assisted by vibrational spectroscopy, thermoanalysis, and DFT calculations. The crystal structures contain tetrahedral [M5+O4]3- anions, representing the first occurrence of Nb and Ta in a tetrahedral oxidic environment. Many representatives of the orthorhombic K3NO4 structure type have been described in the literature with a cubic structure model with disordered O atomic positions. Based on studies on Cs3MO4 (M = P, V, Nb, or Ta), we show here three different effects which can lead to (pseudo)cubic data sets. Two of them are problems of crystallographic nature (overlooked twinning or adverse atomic form factor ratios), but the third one, phase transformation into a plastic crystalline high-temperature modification, leads to a "truly" cubic structure with dynamically disordered (freely rotating) oxometalate anions. This might be of interest with respect to a large and growing number of sulfido- and selenidometalate materials which are today in discussion as solid-state electrolytes and to the mechanism of the unusually efficient ion transport therein.

α-α Coupling-Dominated PPy Film with a Well-Conjugated Structure for Superlong Cycle Life Supercapacitors.

As the electrode of a supercapacitor, polypyrrole (PPy) inevitably suffers from structural rupture during repeated doping/dedoping processes and releases low practical capacitance due to the large amount of aggregation or cross-linking in PPy chains. The coupling mode (α-α, α-β, or β-β coupling) of pyrroles is critical to the conjugated structure, the conductivity, and cycling stability of PPy. Here, we prepared an α-α coupling-dominated PPy film via simple frozen interfacial polymerization. The PPy film with a nanostructure exposes more electrochemical active sites for the electrode, which can enhance the practical capacitance. The high proportion of the α-α coupling mode results in a high degree of large π-conjugation and a planar structure that can effectively improve the reversible ion transport efficiency and promote uniform stress distribution during the charge and discharge process. The assembled symmetric water-based supercapacitor delivers a high specific capacitance of 267.1 F g-1 at 1 A g-1 and 266.7 F g-1 at 5 A g-1 and exhibits an outstanding cycling performance of above 200 F g-1 even after 60,000 cycles.

Synergistic Charge Storage Enhancement in Supercapacitors via Ti3C2Tx MXene and CoMoO4 Nanoparticles.

MXene has emerged as a highly promising two-dimensional (2D) layered material with inherent advantages as an electrode material, such as a high electrical conductivity and spacious layer distances conducive to efficient ion transport. Despite these merits, the practical implementation faces challenges due to MXene's low theoretical capacitance and issues related to restacking. In order to overcome these limitations, we undertook a strategic approach by integrating Ti3C2Tx MXene with cobalt molybdate (CoMoO4) nanoparticles. The CoMoO4 nanoparticles bring to the table rich redox activity, high theoretical capacitance, and exceptional catalytic properties. Employing a facile hydrothermal method, we synthesized CoMoO4/Ti3C2Tx heterostructures, leveraging urea as a size-controlling agent for the CoMoO4 precursors. This innovative heterostructure design utilizes Ti3C2Tx MXene as a spacer, effectively mitigating excessive agglomeration, while CoMoO4 contributes its enhanced redox reaction capabilities. The resulting CoMoO4/Ti3C2Tx MXene hybrid material exhibited 698 F g-1 at a scan rate of 5 mV s-1, surpassing that of the individual pristine Ti3C2Tx MXene (1.7 F g-1) and CoMoO4 materials (501 F g-1). This integration presents a promising avenue for optimizing MXene-based electrode materials, addressing challenges and unlocking their full potential in various applications.

Study on AEMs with Excellent Comprehensive Performance Prepared by Covalently Cross-Linked p-Triphenyl with SEBS Remotely Grafted Piperidine Cations.

A series of SEBS-C6-PIP-yPTP (y = 0-15%) AEMs with good mechanical and chemical stability were prepared by combining the strong rigidity of p-triphenyl, good toughness of SEBS, and excellent stability of PIP cations. After the introduction of a p-triphenyl polymer into the main chain, a clear hydrophilic-hydrophobic phase separation structure was constructed within the membrane, forming a continuous and interconnected ion transport channel to improve ion transport efficiency. Moreover, the molecular chains of the cross-linked AEMs change from chain-like to network-like, and the tighter binding between each molecule increases the tensile strength. The special structure of the six-membered ring makes PIP have a significant constraint effect; when nucleophilic substitution and Hoffman elimination occur at the α and β positions, the required transition state potential energy increases, making the reaction difficult to occur and improving the alkaline stability of the polymer membrane. The SEBS-C6-PIP-15%PTP membrane has the best mechanical properties (Ts = 38.79 MPa, Eb = 183.09% at 80 °C, 100% RH), the highest ion conductivity (102.02 mS. cm-1 at 80 °C), and the best alkaline stability (6.23% degradation at 80 °C in a 2 M NaOH solution for 1400 h). It can be seen that organic-organic covalent cross-linking is an effective means to improve the comprehensive performance of AEMs.

Controllable Synthesis of Flower-like Hierarchical CuCo2S4 Nanostructure Arrays for High-Performance Hybrid Supercapacitors

Transition metal sulfides (TMSs) are considered as attractive materials in the areas of energy storage because of their unique redox properties, excellent electronic conductivity, as well as environmental friendliness. However, poor cyclic stability and limited electrochemical active sites hinder their further application. To address this issue, a flower-like hierarchical CuCo2S4 structure is constructed by a two-step hydrothermal method. In this nanostructure, CuCo2S4 grows outward to form a tightly bound hierarchical structure on the nickel foams (NFs). This oriented structure can provide more laminar gaps for electrolyte ion diffusion, exposing more reaction sites to increase the ion transport efficiency between the layers, reducing the ion transport resistance and improving the reaction kinetics. Thus, the CuCo2S4 electrode exhibits excellent energy storage performance, exhibiting a high specific capacity of 1415.6 F g−1 at 1 A g−1. After 10,000 cycles of 10 A g−1, it still has 91.9% of the initial performance. In addition, an asymmetrical supercapacitor (ASC) was constructed by choosing CuCo2S4 as the anode and RGO as the cathode, which has the maximum energy density (61.8 Wh Kg−1) at 812.1 W Kg−1 and significant cycling endurance (92.05% retention) at 10,000 turns. Briefly, the researchers successfully constructed an array of CuCo2S4 flower-like hierarchical nanostructures and confirmed their potential application in supercapacitors.

ZnCl2-KOH modulation of biomass-derived porous carbon for supercapacitors

ABSTRACT With the implementation of carbon neutrality, more and more researchers are devoted to the development of biomass-based porous carbon materials using agricultural and forestry wastes for energy storage applications. However, biomass-derived carbon materials are still suffering from structural instability and difficult to regulate the pore structure, so it is very essential to study the regulation of pore structure in activation process of biochar. Therefore, this work developed an approach to modulate the pore structure of biomass porous carbon. The pyrolyzed biochar was primary activated by ZnCl2 to form the intermediate FC, and the FC was secondary activated by the impregnation method with the addition of trace KOH to form the graded porous carbon FCK-x. The prepared porous carbon exhibited a large specific surface area (2845 m2g−1) and a large pore volume (1.43 cm3g−1), which is very favorable for efficient ion transport in the three-electrode system, FCK-0.6 exhibited a specific capacitance of 321.7 F/g at 1A/g and the assembled supercapacitor exhibited high capacitance retention (95.17%) and charge retention (85%). This work provides a feasible way to modulate biomass pore structure.

Highly Efficient Aligned Ion-Conducting Network and Interface Chemistries for Depolarized All-Solid-State Lithium Metal Batteries

HighlightsThis study introduces an innovative 3D-printed electrolyte with vertically aligned ion transport network, which contains well-dispersed nanoscale Ta-doped Li7La3Zr2O12 in a poly(ethylene glycol) diacrylate matrix.The 3DSE architecture enables efficient ion transport across the Li/electrolyte and electrolyte/cathode interfaces, which allows for increased active material mass loading and enhanced interfacial adhesion.The p-3DSE Li symmetric cell displays an impressive critical current density value of 1.92 mA cm−2 and stable operation for 2600 h at room temperature. Full cells using p-3DSE achieve notable areal capacities.

Spaced-Confined Janus Engineering Enables Controlled Ion Transport Channels and Accelerated Kinetics for Secondary Ion Batteries.

The large grain boundary resistance between different components of the anode electrode easily leads to the low ion transport efficiency and poor electrochemical performance of lithium-/sodium-ion batteries (LIBs/SIBs). To address the issue, a Janus heterointerface with a Mott-Schottky structure is proposed to optimize the interface atomic structure, weaken interatomic resistance, and improve ion transport kinetics. Herein, Janus Co/Co2P@carbon-nanotubes@core-shell (Janus Co/Co2P@CNT-CS) refined urchin-like architecture derived from metal-organic frameworks is reported via a coating-phosphating process, where the Janus Co/Co2P heterointerface nanoparticles are confined in carbon nanotubes and a core-shell polyhedron. Such a Janus Co/Co2P heterointerface shows the strong built-in electric field, facilitating the controllable ion transport channels and the high ion transport efficiency. The Janus Co/Co2P@CNT-CS refined urchin-like architecture composed of a core-shell structure and the grafting carbon nanotubes enhances the structure stability and electronic conductivity. Benefiting from the spaced-confined Janus heterointerface engineering and synergistic effects between the core-shell structure and the grafting carbon nanotubes, the Janus Co/Co2P@CNT-CS refined urchin-like architecture demonstrates the fast ion transport rate and excellent pseudocapacitance performance for LIBs/SIBs. In this case, the Janus Co/Co2P@CNT-CS refined urchin-like architecture shows high specific capacities of 709 mA h g-1 (200 cycles) and 203 mA h g-1 (300 cycles) at a current density of 500 mA g-1 for LIBs/SIBs, respectively.

Graphene-wrapped Fe2TiO5 nanoparticles with enhanced performance as lithium-ion battery anode

Iron-titanium bimetallic oxide, Fe2TiO5 (FTO), is anticipated to exhibit superior electrochemical properties due to its high theoretical capacity. However, the practical large-scale utilization of FTO is severely hindered by its substantial capacity fading and subpar cycling performance. In this work, we propose a strategy to improve the electrochemical properties of FTO by carbon coating. To implement this strategy, we synthesize FTO nanoparticles (FTO NPs) coated with reduced graphene oxide (rGO) by a solvothermal method. When used as anode materials in lithium-ion batteries, FTO/rGO composite demonstrates a higher specific capacity (498.2 mAh g−1 after 100 cycles) than pristine FTO NPs, which is ascribed to the addition of rGO. The rGO with excellent conductivity facilitates efficient electron and ion transportation, and the composite structure of FTO NPs wrapped with rGO provides buffer space to alleviate the volume expansion during the charge/discharge process.