Excellent High-rate Cycling Stability Research Articles

Dual-vapour-thermal engineering evoking bound water pathways of vanadium oxide for high-rate and durable zinc-ion storage

Vanadium oxides have attracted extensive attention as promising cathode materials for aqueous zinc-ion batteries (AZIBs) owing to their variable valences and laminar structures. However, the strong interaction between divalent Zn2+ and the [VOn] host lattice limits its application. In this study, a facile dual-vapour-thermal engineering strategy was proposed for the first time to reconstruct V2O5 as an advanced cathode for AZIBs. Synchrotron radiation X-ray adsorption and photoelectron spectroscopies revealed that the high pressure and thermal environments of the ethanol/water dual-vapour phase trigger the fast formation of oxygen-deficient vanadium oxide hydrates (VPH-VO) containing rich bound water pathways. The in situ Raman spectra verified that these bound water pathways shield the electrostatic interaction within the lamellar [VOn] host, providing a more favourable environment for Zn2+ diffusion. The VPH-VO cathode delivered an outstanding capacity of 452 mA h g−1 at 0.5 A/g and an excellent high-rate cycling stability of 242 mA h g−1 after 2000 cycles at 10 A/g. Density functional theory calculation disclosed the highly reversible Zn2+ adsorption/desorption and low zinc-ion migration barrier in the bound water pathways of VPH-VO. This pioneering dual-vapour-thermal engineering is an efficient fabrication approach for superior lamellar cathode materials for high-performance AZIBs.

In situ construction of SnO-NiO derived from metal-organic frameworks on nickel foam for energy storage devices

Background: Metal-organic frameworks (MOFs) have concerned substantial research attention as potential electrode materials in the field of electrochemical storage owing to their high porosity. However, their low cycling stability and rapid capacity fading hinder the practical application of MOFs because of the structural instability of the electrodes during cycling. Existing studies have shown that MOF-derived materials are helpful in improving their performance due to controllable functionalities, permanent porosities, and high surface area.Methods: We demonstrated an efficient strategy to solve these problems by combining the beneficial redox properties of Sn and Ni metal precursor and benzene-1,3,5-tricarboxylate (BTC) organic linker. SnONiO derived from Sn-Ni MOFs were in situ deposited on nickel foam (i.e., Sn-Ni MF@Ni nanostructures) by solvo-hydrothermal approach.Significant findings: The all-solid-state asymmetric supercapacitor device, Sn-Ni MF@Ni//AC, exhibited excellent electrochemical storage capacity (214.67 F/g at 1.0 A/g) and excellent high-rate cycling stability of 90% over 6000 cycles. The Sn-Ni MF@Ni//AC nanostructured device exhibited high energy and power densities of 66.87 Wh/kg at 747.67 W/kg, respectively, at a discharge time of 322 s. The remarkable electrochemical storage properties of Sn-Ni MF@Ni nanostructures can be attributed to their unique SnO and NiO bimetallic oxide phases on NF substrates. They are comparable to those of drop-cast Sn-Ni MFs on NF electrodes.

Realizing rapid electrochemical kinetics of Mg2+ in Ti-Nb oxides through a Li+ intercalation activated strategy toward extremely fast charge/discharge dual-ion batteries

The development of practical magnesium batteries is severely hindered by the sluggish solid diffusion processes resulting from the relatively high charge density of Mg2+ with two unit charges. Therefore, exploiting novel charge storage mechanisms to overcome the inherent kinetic obstruction is urgently needed. Herein, the rapid diffusion kinetics of Mg2+ in Wadsley-Roth phase TiNb2O7 (TNO) is realized through the electrochemical Li+ intercalation boosted approach, contributing to the successful fabrication of high-rate and ultra-long lifespan dual-ion batteries. Through adding lithium salt into the conventional all phenyl complex electrolyte, not only Li+ but also Mg2+ can be intercalated into the TNO, implying the intercalation of Mg2+ can be activated by the intercalation of Li+. Meanwhile, theoretical calculations reveal that the insertion of Li+ can significantly improve the electronic conductivity of TNO and reduce the diffusion energy barrier of Mg2+ in TNO. Moreover, in-situ Raman and ex-situ X-ray diffraction measurements also indicate the improved structural integrity of TNO with Li+ pre-intercalation during cycling. Consequently, such a dual-ion battery system with the TNO cathode and Mg metal anode exhibits a high reversible capacity (243.6 mAh g−1 at 0.1 C) and excellent high-rate cycling stability (capacity retention of 85.1% at 5 C after 2000 cycles)

Polysulfides immobilization and conversion by nitrogen-doped porous carbon/graphitized carbon nitride heterojunction for high-rate lithium-sulfur batteries

Improving efficiency of solid-liquid-solid multiphase conversion of sulfur to Li2S and suppressing lithium polysulfide shuttle phenomenon are crucial tasks for industrialization of lithium-sulfur batteries. In this study, a novel honeycomb-like nitrogen-doped porous carbon/graphitized carbon nitride (HPCG) heterojunction nanocatalyst is prepared using truncated rhombic dodecahedral zeolitic imidazolate framework-8 (TRD-ZIF-8) nanoparticles as a synthesis template. A unique hierarchical porous structure and abundant active catalytic sites of HPCG can effectively immobilize polysulfides, accelerate long-chain polysulfide conversion and promote Li2S nucleation, thereby inhibiting the shuttle effect. HPCG cells exhibit good rate performance and excellent high-rate cycling stability with only 0.073% capacity decay per cycle after 1000 cycles at 5 C. Specifically, a cell with a low electrolyte/sulfur (E/S) ratio of 9.6 µL mg−1 demonstrates stable operation over 300 cycles at 1C. This work is expected to deepen the understanding of interphase conversion process of complex lithium polysulfides and provide new ideas for designing sulfur host materials of lithium-sulfur batteries.

Sunflower seed husk-derived submicron carbon spheres and SnO2 nanoparticles composite used as an anode for high-performance lithium-ion batteries

Tin dioxide (SnO2) has a wide range of sources and high specific capacity, it is a forward-looking measure to use it as a lithium-ion battery anode, whereas its performance will hampered rapidly due to large volume expansion in practical applications. In this paper, based on the concept of environmental protection and green experiment, sunflower seed shell was used as raw material, biomass carbon microspheres were synthesized by hydrothermal method, and compounded with SnO2 nanoparticles in a certain proportion. Green biomass-derived carbon submicron spheres and their cross-linked structures can not only shorten the lithium ion transport path, but also reduce the structural damage caused by lithium ion intercalation. In particular, under the premise of carefully controlling the reaction time, those obtained after the reaction time for 24 h presented a promising Li storage properties and electrochemical performance with an excellent high-rate cycling stability of 590.5 mAh g−1 at 1C after 150 cycles. And it can still charge and discharge stably after 100 cycles at 0.2C and has a remarkable specific capacity of 959.2 mA h g−1.

Core-Shell-Type Carbon-Coated Lithium Titanium Oxide Composites Derived from Ti-Based Metal Organic Framework As Anode Materials for Lithium Secondary Batteries

Lithium titanium oxide, Li4Ti5O12 (LTO), is one of the most promising anode materials for Li secondary batteries. Although it has a lower specific capacity of approximately 175 mAh/g than does graphite (372 mAh/g), this material shows the unique property of the negligible lattice change in the Li-ion insertion/desertion process, providing excellent high-rate cycling stability. The biggest obstacles of limiting the application of LTO material electrode are poor electrical conductivity and low lithium-ion diffusion coefficient. To overcome these problems, in this work carbon-coated LTO (LTO/C) composites with core-shell-type structure are synthesized and it is derived from Ti-based metal organic framework (Ti-MOF). For the synthesis of the LTO/C composites, Ti-MOF was chemically lithiated by n-BuLi and heated at different temperature (500-800 oC) in an inert atmosphere. According to powder X-ray diffraction analysis, the as-lithiated sample shows an amorphous structure, and the LTO structure is generated after heat-treatment of above 600 oC. Transmission electron microscopy clearly shows core-shell-type LTO particles surrounded by carbon layers with a thickness of 3-5 nm. The electrochemical measurements clearly demonstrate the promising functionality of the present LTO/C composite as anode for lithium secondary batteries. The LTO/C composite obtained by heating at 700 oC show the largest discharge capacity (cal. 152 mAh/g) with good cyclability. The present experimental findings underscore the validity of the use of MOF as a useful platform for new synthetic strategies of carbon coated LTO materials and also for the improvement of their functionality.

Highly dispersed SnO2 nanoparticles confined on xylem fiber-derived carbon frameworks as anodes for lithium-ion batteries

Abstract Tin oxide (SnO2) has been considered as a promising alternative material for lithium-ion batteries (LIBs) anodes owing to its high specific capacity, low operation potential and high natural abundance. However, its practical performance is hampered by the poor rate capability and fast capacity fading. In this work, we synthesized the highly dispersed SnO2 nanoparticles confined on the xylem fiber-derived carbon frameworks (SnO2@XFC@C) by a facile solvothermal method. The synergy of using open XFs-derived carbon as conductive framework and glucose-derived carbon as matrix enables the superior lithium storage capability of SnO2 materials. Using aqueous electrode proceeding, the SnO2@XFC@C delivers a high discharge capacity of 1810 mAh g−1 with an initial Coulombic efficiency of 85.4%, and excellent high-rate cycling stability (505 mAh g−1 at 1.0 C after 1000 cycles). This structure design offers significant advantages in terms of realization of low cost, high energy and sustainable lithium-ion batteries, and is extendable to other battery systems.

Facile synthesis of carbon embedded dual phase MnO/MnS nanoparticles composite for superior lithium storage performance

Herein, carbon embedded dual phase MnO/MnS nanoparticles (MnO/MnS-C) composite was synthesized through a facile one-step solvethermal method and subsequent heat treatment. Applied to lithium ion batteries anode, the MnO/MnS-C electrode exhibits a high reversible specific capacity (1183 mAh/g at 0.2 A/g after 240 cycles) and an excellent high-rate cycling stability (783 mAh/g at 0.5 A/g after 300 cycles). The superior lithium storage performance of the MnO/MnS-C is mainly ascribed to the presence of carbon matrix, which can not only stabilize the MnS/MnO nanoparticles against self-agglomeration and buffer the volume expansion of the MnS/MnO nanoparticles during lithiation/delithiation, but also enhances the conductivity of whole structure.

Bimetallic metal-organic framework derived Sn-based nanocomposites for high-performance lithium storage

Sn-based materials as potential anode materials have triggered significant research interests for lithium storage owing to their high theoretical capacity and low cost. However, the practical applications of Sn-based materials are hindered by low capacity release and fast capacity fading due to large volume expansion and structural pulverization of the electrodes during cycling. Herein, we demonstrate an efficient strategy to alleviate/resolve the above issues by introducing highly conductive inactive metal to alloy with Sn and then loading the Sn-based alloy particles onto two-dimensional (2D) graphene matrix. The graphene supported Fe–Sn nanoalloy composites (FeSn2/FeSn/Fe-rGO) are synthesized via a facile bimetallic metal-organic framework precursor route, in which Sn3[Fe(CN)6]4 nanocubes are grown in-situ on reduced graphene oxide (rGO) sheets, followed by thermal decomposition of the Sn3[Fe(CN)6]4/rGO precursor in an Ar/H2 atmosphere. As a result, the lithium-ion batteries based on FeSn2/FeSn/Fe-rGO composites exhibit outstanding lithium storage performance with a remarkable reversible capacity of 1274 mAh g−1 at 0.2 A g−1 after 200 cycles, a great rate capability of 665 mAh g−1 at 5.0 A g−1, and excellent high-rate cycling stability with a capacity decay of only 0.025% per cycle within 1200 cycles at 2.0 A g−1. The excellent electrochemical performance of FeSn2/FeSn/Fe-rGO can be ascribed to its unique three-order buffer structures: the Fe atoms in FeSn2 and FeSn acting as tough buffer, metal Fe as framework buffer for cubic nanoparticles, and rGO as 2D elastic matrix buffer, which effectively alleviate the volume expansion and structural pulverization of the electrode during lithiation, synergistically enhance the lithium storage performance.

Nb5+-doped P2-type Mn-based layered oxide cathode with an excellent high-rate cycling stability for sodium-ion batteries

P2-Na0.67Co0.25Mn0.75-xNbxO2 (x = 0, 0.015, 0.030, 0.045) cathode materials were obtained by a simple solid-state method. The Nb5+-doped effects on ameliorating the structural and electrochemical properties of the Na0.67Co0.25Mn0.75O2 parent material for sodium-ion batteries have been investigated. XRD measurements confirm a hexagonal main phase (P63/mmc) and some trace of orthorhombic NaNbO3 (P21ma). Rietveld refinements exhibit the higher lattice parameters and the bigger c/a values due to Nb5+ doping into the parent Na0.67Co0.25Mn0.75O2. The optimized 3.0 at.% Nb5+-doped P2-Na0.67Co0.25Mn0.75O2 sample delivers the initial discharge capacity of 126.7 mAh g−1 at 0.1 C in the voltage range of 1.8–4.0 V, and its capacity retention is 75.3% after 100 cycles, which is 63.7% higher than that of the pristine. Whereas at 10 C rate, the optimized sample presents the maximal discharge capacity of 72.8 mAh g−1 with an excellent high-rate cycling stability of 91.6% retention after 100 cycles, correspondingly the pristine shows 61.4 mAh g−1 and 73.1% retention. These excellent electrochemical performances are ascribed to better structural stability, and lower charge transfer resistance and higher Na+ diffusion coefficient after Nb5+ doping. Therefore, the Nb5+-doped P2-type cathode materials can be deemed as a beneficial improvement for researches on sodium-ion batteries.

Mg–Ti co-doping behavior of porous LiFePO4 microspheres for high-rate lithium-ion batteries

Porous Mg–Ti co-doped LiFePO4 microspheres are successfully synthesized through the feasible carbothermic reduction reaction combined with the spray drying process, showing excellent high-rate cycling stability.

Energetic Aqueous Rechargeable Sodium‐Ion Battery Based on Na2CuFe(CN)6–NaTi2(PO4)3 Intercalation Chemistry

Aqueous rechargeable sodium-ion batteries have the potential to meet growing demand for grid-scale electric energy storage because of the widespread availability and low cost of sodium resources. In this study, we synthesized a Na-rich copper hexacyanoferrate(II) Na2 CuFe(CN)6 as a high potential cathode and used NaTi2 (PO4 )3 as a Na-deficient anode to assemble an aqueous sodium ion battery. This battery works very well with a high average discharge voltage of 1.4 V, a specific energy of 48 Wh kg(-1) , and an excellent high-rate cycle stability with approximately 90 % capacity retention over 1000 cycles, achieving a new record in the electrochemical performance of aqueous Na-ion batteries. Moreover, all the anode, cathode, and electrolyte materials are low cost and naturally abundant and are affordable for widespread applications.

General Solution Growth of Mesoporous NiCo2O4 Nanosheets on Various Conductive Substrates as High‐Performance Electrodes for Supercapacitors

Mesoporous NiCo(2) O(4) nanosheets can be directly grown on various conductive substrates, such as Ni foam, Ti foil, stainless-steel foil and flexible graphite paper, through a general template-free solution method combined with a simple post annealing treatment. As a highly integrated binder- and conductive-agent-free electrode for supercapacitors, the mesoporous NiCo(2) O(4) nanosheets supported on Ni foam deliver ultrahigh capacitance and excellent high-rate cycling stability.

Synthesis of LiFePO 4/C composite with high-rate performance by starch sol assisted rheological phase method

LiFePO 4/C composite was synthesized at 600 °C in an Ar atmosphere by a soluble starch sol assisted rheological phase method using home-made amorphous nano-FePO 4 as the iron source. XRD, SEM and TEM observations show that the LiFePO 4/C composite has good crystallinity, ultrafine sphere-like particles of 100–200 nm size and in situ carbon. The synthesized LiFePO 4 could inherit the morphology of FePO 4 precursor. The electrochemical performance of the LiFePO 4 by galvanostatic cycling studies demonstrates excellent high-rate cycle stability. The Li/LiFePO 4 cell displays a high initial discharge capacity of more than 157 mAh g −1 at 0.2C and a little discharge capacity decreases from the first to the 80th cycle (>98.3%). Remarkably, even at a high current density of 30C, the cell still presents good cycle retention.

Structural and electrochemical characterization of LiFePO 4 synthesized by an HEDP-based soft-chemistry route

High performance LiFePO 4 cathode material was synthesized by an HEDP-based soft-chemistry method, followed by calcination at 700 °C for 5 h in Ar. The synthesized LiFePO 4 was characterized by XRD, SEM techniques. The results showed that the LiFePO 4 powder has good crystallinity and the diameter of the powder ranges form 50–300 nm. The electrochemical performance of the LiFePO 4 by galvanostatic cycling studies demonstrated excellent high rate cycle stability. What noticeable is that the material has very flat voltage plateaus and the voltage difference is only about 0.3 V between the plateaus of charge and discharge even at a high rate of 10 C. This suggests excellent transport properties of the sample leading to a minimized kinetic polarization.