Electrochemical Kinetic Performances Research Articles

Ni/Mn electroactive nanohybrids physic-chemical properties for ulterior new generation of supercapacitors

In this paper, highly mesoporous hierarchical mono- and bi- Ni and/or Mn based hydroxide and/or carbonate nanohybrids were synthesized using a facile free template hydrothermal method and investigated as high-performance electroactive nanomaterials for ulterior new generation of supercapacitors. Controlling the Ni/Mn precursors molar ratio and the growth conditions can offer preponderances for performances enhancing via a comparative products physic-chemical properties which were carried out using different techniques like: XRD, FTIR, Raman, XPS, HRTEM/FESEM, EDS, UV–visible and BET. The structural results confirmed the formation of MnCO3, α-3Ni(OH)2·2H2O and Ni(HCO3)2 phases in the synthesized nanomaterials, with different morphologies (nanofibers, nanocubes, porous micro/nanoflowers) depending on the hydrothermal synthesis conditions. Meanwhile, the influence of Ni and Mn transition metal species co-existence on the resulting composition and their optical properties were also discussed. Moreover, their electrochemical measurements were also performed in a 6 M KOH aqueous electrolyte using three electrode system. The results show that 2Ni(HCO3)2/MnCO3 nanohybrid exhibited the highest specific capacitance (capacity) of 2777 F g−1 at 5 mV s−1 (320 mAh.g−1 at 1 A g−1) with high rate capability. This excellent electrochemical kinetics performance is ascribed to the optimized composition of Ni/Mn and its unique nanostructured configuration with intercalated ions, indicating a great potential of this new kind of nanohybrids to deliver both high energy density and high power density in future energy storage devices.

Microstructure and electrochemical properties of cobalt-substituted A2B7-type La–Y–Ni-based hydrogen storage alloys

La–Y–Ni-based superlattice hydrogen storage alloys exhibit key technological advantages as negative electrode materials for Nickel-metal hydride (Ni-MH) batteries; however, the function of Co has not been studied systematically. A series of LaY2Ni10-xMn0.5Cox (x = 0, 0.3, 0.5, and 0.9) alloys with only A2B7-type phases were prepared in this study, and the effects of Co on the microstructure and electrochemical properties were studied. Co has a minor effect on phase composition; however, it increased cell parameters because of its larger atomic size compared to that of Ni. Co-substituted alloys exhibited excellent activation performance and achieved the maximum discharge capacity in the first cycle. Moreover, Co promoted the discharge capacities of the alloys, but aggravated cycling degradation attributed to the accelerated pulverisation of the alloy particles that leads to serious oxidation/corrosion. Furthermore, an appropriate amount of Co enhances the electrochemical kinetics performance by promoting the charge transfer rates on the alloy surface and the hydrogen diffusion rates in the alloy bulk.

Excellent ion storage properties of copper-cobalt composite selenide heterostructure in magnesium/lithium hybrid battery

Rechargeable magnesium batteries (RMBs) have emerged as a promising alternative to lithium-ion batteries (LIBs), given their high abundance and desirable safety characteristics. However, the strong polarization of divalent ions has hindered the satisfactory insertion and dissolution of Mg2+ ions in the cathode, thereby limiting the electrochemical performance of the system. To address this issue, magnesium/lithium hybrid batteries (MLHB) have been developed, using both Mg2+ and Li+ ions as carriers to enhance the electrochemical kinetic performance and maintain safety. In this study, a Cu2Se/CoSe heterostructured cathode is designed to extremely promote the electrochemical performance of MLHB. When it is applied to MLHB, the battery exhibites extremely high initial discharge capacity, reversible capacity and cycling stability. The initial discharge capacity obtains 385 mAh g−1 at 100 mA g−1, and a reversible capacity of 140 mAh g−1 is maintained after 200 cycles. The role of the special heterostructures and the effect of pre-lithiation on cathode materials are discussed in detail, on the basis of which a two-step storage mechanism of hybrid ions in Cu2Se/CoSe is proposed. This work lays the foundation for designing and constructing high-capacity, excellent cycle stability cathodes with fast charge-transfer kinetics.

Understanding lanthanum effects on the structure and properties of LaxY1−xMgNi4 hydrogen storage alloys

This study mainly concentrated on investigating the effects on the crystal structure, hydrogen storage, and electrochemical properties of LaxY1−xMgNi4 (x = 0, 0.25, and 0.5) alloys. The refined X-ray diffraction patterns reveal the substitution by La results in a change in the phase composition and abundance of the compound and an increase in the lattice constants. La can increase the maximum hydrogen absorption capacity while decreasing the hydrogen absorption and desorption plateaus. However, increasing the La content leads to incomplete hydrogen desorption. In electrochemistry, La addition can improve the activation property, while the electrodes with higher Y content show better cycling stability. The La0 25Y0.75MgNi4 alloy exhibits a maximum capacity for discharge of ∼400 mAh g−1 @10 mA g−1. Its superior electrochemical kinetic performance is attributed to a higher hydrogen diffusion coefficient and exchange current density. Therefore, by optimizing the La content, the tested alloys' hydrogen storage, and electrochemical performance can be improved.

Ta4C3-Modulated MOF-Derived 3D Crosslinking Network of VO2(B)@Ta4C3 for High-Performance Aqueous Zinc Ion Batteries

A two-dimensional MXene (Ta4C3) was innovatively used herein to modulate the space group and electronic properties of vanadium oxides, and the MXene/metal-organic framework (MOF) derivative VO2(B)@Ta4C3 with 3D network cross-linking was prepared, which was then employed as a cathode to improve the performance of aqueous zinc ion batteries (ZIBs). A novel method combining HCl/LiF and hydrothermal treatments was used to etch Ta4AlC3 to obtain a large amount of accordion-like Ta4C3, and the V-MOF was then hydrothermally grown on the surface of the stripped Ta4C3 MXene. During the annealing process of V-MOF@Ta4C3, the addition of Ta4C3 MXene liberates the V-MOF from agglomerative stacking, allowing it to show additional active sites. More significantly, Ta4C3 prevents the V-MOF in the composite structure from converting into V2O5 of space group Pmmn but into VO2(B) of space group C2/m after annealing. A considerable advantage of VO2(B) for Zn2+ intercalation is provided by the negligible structural transformation during the intercalation process and the special tunnel transport channels, which have an enormous area (0.82 nm2 along the b axis). According to first-principles calculations, there is a strong interfacial interaction between VO2(B) and Ta4C3, which deliver remarkable electrochemical activity and kinetic performances for the storage of Zn2+. Therefore, the ZIBs prepared with the VO2(B)@Ta4C3 cathode material exhibit an ultra-high capacity of 437 mA h·g-1 at 0.1 A·g-1 while showing good cycle performance and dynamic performance. This study will offer a fresh approach and a reference for creating metal oxide/MXene composite structures.

Hierarchical TiO2 nanoflowers percolated with carbon nanotubes for long-life lithium storage

Titanium dioxide (TiO2) is a promising anode materials for lithium-ion batteries due to its advantages such as good safety, reliability, reversible capacity, high content and environmental friendliness. However, its inherent defects such as low ion diffusion coefficient and poor electrical conductivity seriously limit its practical application. In this study, we designed a unique hybrid structure of TiO2 nanoflowers percolated with carbon nanotubes (CNTs) by a low cost solution method. The hierarchical structure of TiO2 increases the specific surface area and shortens the ion/electron transport distance. CNTs are uniformly embedded in the interior of TiO2 nanoflowers to improve the overall conductivity and flexibility. As a result, the optimized TiO2@CNTs as lithium ion battery (LIBs) anode, showed excellent long-term cycle performance (177.5 mA h g−1, at 1.0 A g−1 after 600 cycles). The excellent reversibility and electrochemical kinetic performance are also studied by CV and EIS measurements. This work provides a new perspective for exploring efficient lithium storage for high performance anode materials.

Electrochemical kinetic study and performance evaluation of surface-modified mesoporous sodium carbonophosphates nanostructures for pseudocapacitor applications

Sodium carbonophosphates as a novel low-cost and safe electrode material have been widely researched for sodium and lithium-ion battery application. Here, we report the pseudocapacitive behavior of the surface-modified mesoporous Na3MCO3PO4 (M=Ni, Co, Mn and Cu) nanostructure compounds in 1 M KOH electrolyte at room temperature. The electrochemical kinetic performances are studied using cyclic voltammetry (CV) cycled from 10 mVs−1 to 100 mVs−1. The electrodes are found to follow different kinetic behaviors depending on the scan rate. Overall, the deep reconstructed Na3CoCO3PO4 (Co(OH)2/Co3O4 agglomerated nanoplates) electrode provided a high specific capacitance compared to the deep reconstructed Na3MnCO3PO4 (Mn(OH)2/Mn3O4) and surface-modified Na3NiCO3PO4 (Ni(OH)2/Na3NiCO3PO4) and Na3CuCO3PO4 (Cu(OH)2/Na3CuCO3PO4) based electrodes at the current density of 20 Ag−1. The fabricated symmetric supercapacitor based on the Co(OH)2/Co3O4 delivered an energy density of 14.5 Wh kg−1 at the ultrahigh power density of 20 kW kg−1 demonstrating its excellent rate performance suitable for electric vehicle applications. The surface-modified Ni(OH)2/Na3NiCO3PO4 based SSC device showed high retention of 116% initial capacitance after 70,000 charging–discharging cycles, revealing excellent cycling stability.

An Electric-Field-Reinforced Hydrophobic Cationic Sieve Lowers the Concentration Threshold of Water-In-Salt Electrolytes.

High-concentration water-in-salt (WIS) electrolytes expand the stable electrochemical window of aqueous electrolytes, leading to the advent of high-voltage (above 2V) aqueous Li-ion batteries (ALIBs). However, the high lithium salt concentration electrolytes of ALIBs resultin their high cost and deteriorate kinetic performance. Therefore, it is challenging for ALIBs to explore aqueous electrolytes with appropriate concentration to balance the electrochemical window and kinetic performance as well as the cost. In contrast to maintaining high concentrations of aqueous electrolytes (>20m), a small number of hydrophobic cations are introduced to a much lower electrolyte concentration (13.8m), and it is found that, compared with WIS electrolytes, ALIBs with these concentration-lowered electrolytes possess a compatible stable electrochemical window (3.23V) and achieve better kinetic performance. These findings originate from the added cations, which form an electric-field-reinforced hydrophobic cationic sieve (HCS) that blocks water away from the anode and suppresses the hydrogen evolution reaction. Meanwhile, the lower electrolyte concentration provides significant benefits to ALIBs, including lower cost, better rate capability (lower viscosity of 18cP and higher ionic conductivity of 22mScm-1 at 25°C), and improved low-temperature performance (liquidus temperature of -10.18°C).

Preparation of carbon nanofiber supported Co nanoparticles for improving the electrochemical hydrogen storage properties of Co9S8 alloy

Co9S8 alloy was synthesized through mechanical ball milling, and cobalt/carbon nanofiber (Co/CNF) was prepared by the electrospinning process. The addition of Co and CNF increased the discharge capacity of Co9S8 to 563.4 mA/g. Furthermore, the composite electrode exhibited superior high-rate discharge capability, corrosion resistance, and other kinetic properties. CNF provides high conductivity and more reaction sites for Co nanoparticles. Co nanoparticles participate in redox reactions and show a catalytic effect. Moreover, the synergistic effect of CNF and Co also promotes the electrochemical hydrogen storage and kinetic performances of Co9S8 alloy.

Cellulose/lignin-based carbon nanobelt aerogels coating on VSe2 nanosheets as anode for high performance potassium-ion batteries

Potassium-ion batteries (PIBs) have attracted high attention in recent years due to the low cost, low redox potential and abundant naturally storage. However, PIBs has been hampered by the large K+ ion and huge volumetric change, which lead to the poor electrochemical kinetic and cycling performance. Herein, the cellulose/lignin-based carbon nanobelt aerogels coating on VSe2 nanosheets (VSe2@CNB) as anode materials for PIBs has been fabricated for the first time by the selenization of VO(acac)2 and subsequent polymerization and coating by carbon nanobelt aerogels. The enhancing in the conductivity and the structural protection have been provided by the interlinked, high surface area and porosity carbon nanobelt aerogels, the VSe2@CNB shows improved potassium-storage performance, obtains high reversible capacity of 227.4 mAhg−1 at 100 mAg−1 after 100 cycles, as well as delivering long-term cycling stability of 125 mAhg−1 at 500 mAg−1 after 1000 cycles with high columbic efficiency (99%). Ex situ X-ray diffraction (XRD) and transmission electron microscope (TEM) measurement indicate that the reversible phase evolution for the storage potassium mechanism of the VSe2@CNB composite consists of K+ insertion into the layer of VSe2 nanosheets and conversion reaction of VSe2 transfer into K2Se.

Preparation and electrochemical performance of MWCNT/MoS2 composite modified Co–P hydrogen storage material

The MoS2 interwoven with multi walled carbon nanotubes (MWCNT/MoS2) composite is synthesized by solvothermal method. The Co–P material is obtained via mechanical alloying. Composites of Co–P coated with MoS2, MWCNT and different amounts of MWCNT/MoS2 are fabricated by ball-milling. Eventually, MWCNT/MoS2 coated Co–P electrode exhibits superior discharge capacity than separate MoS2 or MWCNT modified Co–P and original Co–P. The highest discharge capacity of 653.9 mA h/g is obtained for Co–P + 6% MWCNT/MoS2. The preferable HRD, corrosion resistance and kinetics properties are also achieved after MWCNT/MoS2 loading. Due to the synergistic effect between MoS2 and MWCNT, the Co–P + MWCNT/MoS2 electrode shows improved electrochemical activity and kinetics performance. The high conductive MWCNT and active MoS2 species within the unique structure of MWCNT/MoS2 can further accelerate the hydrogen diffusion during the electrochemical hydrogen storage process.

Experimental investigation of electrode cycle performance and electrochemical kinetic performance under stress loading* *Project supported by the Major Program of the National Natural Science Foundation of China (Grant No. 11890680) and the National Natural Science Foundation of China (Grant No. 12022205).

Lithium-ion batteries suffer from mechano–electrochemical coupling problems that directly determine the battery life. In this paper, we investigate the electrode electrochemical performance under stress conditions, where seven tensile/compressive stresses are designed and loaded on electrodes, thereby decoupling mechanics and electrochemistry through incremental stress loads. Four types of multi-group electrochemical tests under tensile/compressive stress loading and normal package loading are performed to quantitatively characterize the effects of tensile stress and compressive stress on cycle performance and the kinetic performance of a silicon composite electrode. Experiments show that a tensile stress improves the electrochemical performance of a silicon composite electrode, exhibiting increased specific capacity and capacity retention rate, reduced energy dissipation rate and impedances, enhanced reactivity, accelerated ion/electron migration and diffusion, and reduced polarization. Contrarily, a compressive stress has the opposite effect, inhibiting the electrochemical performance. The stress effect is nonlinear, and a more obvious suppression via compressive stress is observed than an enhancement via tensile stress. For example, a tensile stress of 675 kPa increases diffusion coefficient by 32.5%, while a compressive stress reduces it by 35%. Based on the experimental results, the stress regulation mechanism is analyzed. Tensile stress loads increase the pores of the electrode material microstructure, providing more deformation spaces and ion/electron transport channels. This relieves contact compressive stress, strengthens diffusion/reaction, and reduces the degree of damage and energy dissipation. Thus, the essence of stress enhancement is that it improves and optimizes diffusion, reaction and stress in the microstructure of electrode material as well as their interactions via physical morphology.

The effect of ethyl cellulose coating on the surface of silicon–carbon composite as lithium anode material

The silicon nanoparticles are loaded on the surface of graphite to prepare the silicon–carbon composite as lithium anode material. The first charge and discharge capacity of silicon–carbon composite is 644 and 739.6 mAh g−1, with the initial coulombic efficiency is 89.84%, and the capacity retention rate after 450 cycles is 65.23%. Moreover, the electrochemical performance of ethyl cellulose coated silicon–carbon composite has been investigated. The electrochemical kinetics performance such as charge transfer ability and lithium-ion diffusion are influenced by ethyl cellulose coating. However, the silicon nanoparticles were better bonded on the graphite carrier and less exposed on the surface after ethyl cellulose coating, which is benefit to decrease silicon nanoparticles split away from silicon–carbon composite and stabilize SEI film. Furthermore, the volume expansion is inhibited, so the cycle performance is obviously improved. The first reversible capacity of 5 wt% and 10 wt% ethyl cellulose coated silicon–carbon composite are 632.9 mAh g−1 and 593.3 mAh g−1 with capacity retention rate of 71.40% and 74.68% after 450 cycles, respectively.

Atomic Doping and Anion Reconstructed CoF2 Electrocatalyst for Oxygen Evolution Reaction

AbstractElectrocatalytic water splitting is one of the most promising green solutions for large‐scale hydrogen production, which has developed rapidly in recent years. The slow reaction rate of oxygen evolution reaction (OER) has become the bottleneck to improve the electrocatalytic efficiency. Herein, Fe‐doped CoF2 nanowire arrays on 3D nickel foam are prepared by two steps of hydrothermal reaction and fluorination process. The increased catalytic activity sites and accelerated charge transfer rate make the self‐supported Fe‐doped CoF2 electrode show excellent OER performance in alkaline electrolyte. An overpotential of 230 mV is only required to release a current density of 10 mA cm−2. The Tafel slope derived from the polarization curves is 59 mV dec−1, indicating outstanding electrochemical kinetics performance. A stable output current density of 84 mA cm−2 for more than 96 h is achieved under an invariant overpotential of 338 mV, attributing to the anion reconstruction making part of CoF2 transform into cobalt hydroxide and further improving its electrocatalytic performance.

Superior Electrochemical and Kinetics Performance of LiNi0.8Co0.15Al0.05O2 Cathode by Neodymium Synergistic Modifying for Lithium Ion Batteries

The nickel-rich layered cathode material LiNi0.8Co0.15Al0.05O2 (NCA) is receiving enormous attention for its high energy density and low cost. Nevertheless, its wide application is limited by its unsatisfactory cycle performance and rate performance. In this study, the synergetic modification of the Nd2AlO3N coating and Nd3+ doping is realized to enhance the electrochemical performance of NCA. The Nd2AlO3N coating can protect the electrode-electrolyte interface and inhibit the side reactions. In the meantime, the Nd3+ doping, with the larger ion radius of Nb3+ and stronger Nd-O bond energy, can effectively enhance the kinetics performance and stabilize the crystal structure of the NCA cathode material. The modified materials with above characters demonstrate an excellent electrochemical stability and kinetics performance, among which the Nd4000 sample has the quite best performance, and its capacity/capacity retention still reach 168 mAh·g−1/91% after 200 cycles, which are distinctly higher than the pristine 144.6 mAh·g−1/78.5%. The electrochemical impedance spectra and cyclic voltammetry results also demonstrate that the charge transfer resistance and electrode polarization are suppressed with neodymium modifying during the cycle, and the lithium ion diffusion coefficient is significantly increased compared with the pristine sample.

Promoting electrochemical performances of vanadium carbide nanodots via N and P co-doped carbon nanosheets wrapping

Abstract High theoretical specific capacity, good electrical conductivity, intrinsically stable metallic nature, excellent thermal stability and corrosion resistance enable vanadium carbide (VC) as a promising anode material for sodium-ion and lithium-ion batteries (SIBs and LIBs). However, drastic structural change during cycling and poor electrochemical kinetic performance both make the application of VC in dilemma. Herein, VC nanodots were successfully embedded in N and P co-doped carbon nanosheets (NPC) via a simple wet chemical process followed by high-temperature calcination. Benefiting from the carbon based conductive network and supporting structure for the rapid ion transport and alleviative volume change in VC, the VC@NPC hybrid exhibits a high reversible capacity (250 mA h g−1 at 0.1 A g−1 after 200 cycles), superior rate capability (88 mA h g−1 at a current density of 5.0 A g−1), and excellent cycle performance (97% capacity retention for 600 cycles at 1.0 A g−1) when evaluated as an anode material for SIBs. Besides, as for LIBs, VC@NPC also shows a high capacity of 532.2 mAh g−1 after 200 cycles at 0.1 A g−1 and 216.6 mAh g−1 after 500 cycles at 1.0 A g−1. This study provides a unique nanocomposite system to achieve a superior electrochemical performance and may pave the way for the further design and construction of novel transition metal carbide anode materials for SIBs, LIBs and other areas.

Improved Electrochemical Kinetic Performances of La-Mg-Ni-based Hydrogen Storage Alloy Modified by Ni-Polypyrrole Complex Surface Treatment

In order to improve the electrochemical kinetic performances of La-Mg-Ni-based alloy, complex surface modification of Ni with excellent catalytic activity and conducting polymer polypyrrole(PPy) was performed via electroless plating method. FESEM images revealed that the complex Ni-PPy treatment resulted in more micropores at the alloy surface, with Ni particles and cotton fiber-shape PPy microspheres attached. Both the larger surface area induced by the micropore and the higher catalytic activity and conductivity on account of the dispersed Ni particles/PPy microspheres promoted the electrode reaction, thereby increasing the discharge capacity of the modified alloy electrode. Electrochemical impedance spectroscopy(EIS) and linear polarization results showed that the Ni-PPy treatment decreased the charge-transfer resistance and increased the exchange current density greatly, far more than the single-component Ni or PPy treatment. Consequently, a notable improvement in high rate dischargeability(HRD) was observed, and at a high discharge current density of 1800 mA/g, the HRD of the modified electrode increased by 10.4% compared with that of the bare electrode.

Studying of electrochemical discharging and kinetic properties of Ni-TiF3-CeMg12 composite materials with nanocrystalline and amorphous structure

The ball milling technology was used for fabricating CeMg12/Ni/TiF3 hydrogen materials. The effect of TiF3 content on microstructures and electrochemical performances of the milling alloys was investigated in detail. The microstructures were characterized by scanning electron microcopy (SEM), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM). The electrochemical hydrogen storage properties were tested by discharging capacity and cycling stability. The electrochemical kinetic characteristics were further analyzed with high rate discharging ability (HRD), electrochemical impedance spectroscopy (EIS) technique, hydrogen diffusion behavior (the diffusion coefficient was denoted by D) and apparent activation energy (ΔE). The results reveal that the addition of TiF3 notably enhances the glass forming ability of alloy sample. The maximum discharge capacity of experimental alloy first goes upward from 1060 to 1250 mA h/g then decreases to 1050 mA h/g with TiF3 content is increased from 0 to 5 wt.%. The milling CeMg12-Ni-TiF3 (5 wt.%) alloy shows the best electrochemical cycle stability. The milled CeMg12-Ni-TiF3 (3 wt.%) alloy has optimum electrochemical kinetic performances, which is responsible for the smallest surface activation energy and the fastest hydrogen diffusion rate.

Improved hydrogen storage kinetics of nanocrystalline and amorphous Ce-Mg-Ni-based CeMg12-type alloys synthesized by mechanical milling.

In this paper, ball milling was used to prepare CeMg11Ni + x wt% Ni (x = 100, 200) alloys having nanocrystalline and amorphous structures. The structures of the alloys and their electrochemical and gaseous kinetic performances were systematically investigated. It was shown that the increase in Ni content was beneficial to the formation of nanocrystalline and amorphous structures, and it significantly enhanced the electrochemical and gaseous hydrogen storage performances of as-milled alloys. In addition, the hydrogen storage capacities of the alloys fluctuated greatly with variation in milling duration. The maximum values of hydrogen capacity detected by varying the milling durations were 5.949 wt% and 6.157 wt% for x = 100 and 200 alloys, respectively. Similar results were observed for the hydriding rates and high-rate discharge abilities (HRD) of the as-milled alloys. The dehydriding rate increased with the increase in milling duration. The reduction in hydrogen desorption activation was the reason for enhanced gaseous hydrogen storage kinetics.

Titanium-doped Li2FeSiO4/C composite as the cathode material for lithium-ion batteries with excellent rate capability and long cycle life

Li2Fe1-xTixSiO4/C cathode materials are designed and realized by a facile sol-gel method. The effects of various Ti doping amounts on the microstructure and electrochemical performance of Li2FeSiO4/C are investigated comprehensively. X-ray powder diffraction result confirms the crystal structure of Li2Fe1-xTixSiO4/C to be monoclinic Li2FeSiO4 with minor decrease in the unit cell volume. X-ray photoelectron spectroscopy shows that Ti does successfully dope into the crystal structure of Li2FeSiO4. Galvonostatic charge-discharge experiments are used to study the electrochemical performance of Ti-doped Li2FeSiO4/C as a lithium-ion batteries cathode material. As results, Li2Fe0.98Ti0.02SiO4/C exhibits the best electrochemical performance with the discharge capacity of 102.8 and 91.1 mAh g−1 even at 5 and 10 C (1 C = 165 mA g−1) high rate after 1000 cycles. Additionally, the electrochemical kinetic performance of Li2Fe1-xTixSiO4/C is further determined by electrochemical impedance spectroscopy, cyclic voltammetry and galvanostatic intermittent titration technique. The results indicate that the enhanced electrochemical performance can be attributed to the effect of Ti doping, which not only enhances the structural stability, but also improves the kinetic properties of Li2FeSiO4/C.