Electrochemical Performance For Lithium-ion Batteries Research Articles

Mo-doping modulated cationic vacancy in Zn3V2O8 with enhanced electrochemical performance for lithium-ion batteries

Given diverse redox reactions and abundant raw materials, Zn3V2O8 with high specific capacity is considered as a potential anode material for lithium-ion batteries. Same as other transition metal oxides, Zn3V2O8 suffers from infertile conductivity, sluggish ion diffusion and fast capacity loss derived from volume expansion during discharge/charge process, further hindering its application. In this work, a novel Mo doped Zn3V2O8 (Zn3V2-xMo5x/6O8) anode material with cationic vacancy (V vacancy) has been designed through a facile sol-gel method. It is found that a small Mo-doping amount has nearly no influence on the crystal structure, morphology and element valence states of Zn3V2O8. Mo doped Zn3V2O8 samples possess smaller charge transfer resistance and higher lithium ion diffusion coefficient. The results of electrochemical performance illustrate that Mo doped Zn3V2O8 can deliver higher reversible specific capacities and better rate capability compared with Zn3V2O8, which can be ascribed to the introduction of V vacancy. In particular, when Mo-doping amount is set as 0.03, the obtained Zn3V1.97Mo0.025O8 exhibits a reversible capacity of 481.1 mAh g−1 after 600 cycles at 1 A g−1. It is believed that this work could provide an effective and feasible strategy to construct high performance transition metal vanadate anode materials for lithium-ion batteries.

Designing high-chaos mixed-salt electrolytes for enhancing graphite-electrolyte interfacial stability in lithium-ion batteries

The interfacial stability between graphite anodes and electrolytes is crucial for the electrochemical performance of lithium-ion batteries, particularly at low temperatures. This study investigates the effect of incorporating four common Solid-Electrolyte Interphase (SEI) components—LiF, LiNO3, Li2O, and Li2CO3—directly into two types of commercial electrolytes: carbonate-based (1.0 M LiPF6-EC/DMC, LP30) and ether-based (1 M LiTFSI-DOL/DME+2 % LiNO3, LDD) both with 5 % FEC (v/v) to create high-chaos mixed-salt electrolytes (LP30-FEC-4S and LDD-FEC-4S). Our findings show that Li/graphite cells exhibit significantly enhanced rate performance in both LP30-FEC-4S and LDD-FEC-4S electrolytes, compared to commercial LP30 and LP57 electrolytes. LiFePO4/graphite full cells using LP30-FEC-4S and LDD-FEC-4S electrolytes also showed excellent electrochemical performance (124.73 mAh g−1 and 119.21 mAh g−1 specific capacities at 0.5C). Remarkably, stable SEIs form rapidly on the graphite anode surfaces in the designed electrolytes even at low temperatures of −10 °C. Moreover, we demonstrate that the Li+ solvation structure is fundamental in determining the overall electrochemical performance. This study suggests that enhancing the mixing entropy of the system by adding multiple lithium salts to a commercial electrolyte is an effective and cost-efficient strategy for improving graphite-electrolyte compatibility.

Design and Mechanism Study of High-Safety and Long-Life Electrolyte for High-Energy-Density Lithium-Ion Batteries.

Although nonflammable electrolytes are beneficial for battery safety, they often adversely affect the electrochemical performance of lithium-ion batteries due to their poor compatibility with electrodes. Herein, we design a nonflammable electrolyte consisting of cyclic carbonate and 2,2-difluoroethyl acetate (DFEA) solvents paired with several surface-film-forming additives, significantly improving the safety and cycling performance of NMC811||SiOx/graphite pouch cells. The DFEA solvent exhibits not only good flame retardancy but also lower lowest unoccupied molecular orbital (LUMO) energy, promoting the formation of a robust inorganic-rich and gradient-architecture hybrid interface between the SiOx/graphite anode and electrolyte. The double insurance of good flame retardancy of the DFEA solvent and decreased exothermic effects of both bulk electrolyte and DFEA-derived solid electrolyte interphase (SEI) can ensure the high safety of the pouch cell. Moreover, the highly robust SEI can prevent the excessive reduction decomposition of the electrolyte and alleviate the structural decay of the anode, which can restrain the formation of lithium deposition on the anode surface and further suppress the structural decay of NMC materials. This contributes to the unprecedented cycling performance of the NMC811||SiOx/graphite pouch cells with a capacity retention of 80% after 1000 cycles at a 0.33C rate.

Ti-Doped Co-Free Li1.2Mn0.6Ni0.2O2 Cathode Materials with Enhanced Electrochemical Performance for Lithium-Ion Batteries

Cobalt-free manganese-based lithium-rich layered oxides (LLOs) have garnered research attention as prospective lithium-ion cathode materials owing to their large specific capacity and low price. However, their large-scale application is hindered by their low Coulombic efficiency, poor cycling performance, voltage attenuation, and structural phase transition. To address these issues, the LLO structure is modified via Ti doping at the manganese site herein. Ti-doped Li1.2Mn0.6−xTixNi0.2O2 (x = 0, 0.03, 0.05, 0.10, and 0.15) is prepared using the high-temperature solid-state method. The Ti-doped Li1.2Mn0.6Ni0.2O2 is calculated via first principles. The results show that Ti4+ doping improves the cycle stability and rate performance of Li1.2Mn0.6Ni0.2O2. Electrochemical test results show that the sample exhibits enhanced electrochemical performance when the Ti doping amount is 0.05. The discharge specific capacity at 0.1C is 210.4 mAh·g−1, which reaches 191.1 mAh·g−1 after 100 cycles, with a capacity retention rate of 90.7%. This study proves the feasibility of using cheap cobalt-free LLOs as cathode materials for LIBs and provides a novel system for exploiting low-cost and high-performance cathode materials.

NiSe2/CoSe2 heterostructure nanoparticles anchoring on graphene for enhanced Li-ions storage

Selenide anodes have been extensively studied due to their exceptional electrochemical performance in lithium-ion batteries (LIBs). However, selenides suffer from inadequate specific capacity and high mechanical stress/strain resulting from significant volume changes during cycling. This leads to a rapid reduction in capacity and reversibility, which limits their practical application. Nanoscale bimetallic heterostructure selenides can effectively reduce the lattice vibration induced by lithiation/delithiation and improve the lithium storage capacity and cycle life. This study describes the preparation of NiSe2 and CoSe2 nanoparticles anchored on graphene (NiSe2/CoSe2/Graphene) using freeze-drying and thermal selenization methods. The graphene, selenide particles, and electric field between heterostructure interfaces significantly enhance electrical conductivity, provide active species storage sites, and improve lithium-ion adsorption ability, resulting in high storage capacity and excellent cycling stability. The NiSe2/CoSe2/Graphene composite exhibited a specific capacity of 929.6 mAh g−1 after 320 cycles at a current density of 100 mA g−1. Even at a high current density of 1000 mA g−1, the composite was stably cycled for 1250 cycles with a continuous increase in specific capacity. This study provides valuable insights into the use of bimetallic selenides for improved lithium storage.

Synthesis of submicron-sized LiNi0.5Co0.2Mn0.3O2 cathode particles via reverse microemulsion method: Tailoring size, interfacial properties, and enhanced electrochemical performance for lithium-ion battery

This study explores the impact of submicron-sized cathode materials on lithium-ion battery performance, an area with limited prior research due to synthetic challenges. Employing the reverse microemulsion method, LiNi0.5Co0.2Mn0.3O2 (NCM) cathode particles with tunable sizes (180 nm to 340 nm) were synthesized. Notably, NCM6.67-4.5, which prepared under the volume ratio of the oil phase to the water phase (i.e. 6.67) and applying 4.5 mL NH4OH as the complexing agent, obtained the largest particle size (340 nm). Further investigation revealed that NCM6.67-4.5 exhibited superior discharge specific capacity (177.54 mAh·g−1) and a high coulomb efficiency (99.5 %). The larger particle size in the submicron range facilitated heightened lithium-ion diffusion rates and reduced polarization. Focused Ion Beam-Scanning Electron Microscopy (FIB-SEM) confirmed that increased particle size diminishes specific surface area, mitigating interfacial side reactions during battery cycling. This research underscores the importance of controlling cathode particle size for optimizing electrochemical performance in lithium-ion batteries.

Cation mixing regulation of cobalt-free high-nickel layered cathodes enables stable and high-rate lithium-ion batteries

The cobalt-free high-nickel layered oxide possesses high capacity and controllable cost, positioning it as a prospective option for cathode materials in the future lithium-ion batteries (LIBs). However, the charge compensation effect and high nickel content usually cause serious cation mixing, resulting in poor capacity stability, and hindering its practical application. Here, three types of LiNi0.9Mn0.1O2 microspheres with varying levels of cation mixing are constructed by simply adjusting the calcination temperatures, and the impacts of cation mixing on the electrochemical performance in LIBs are systematically investigated. By using XRD and cross-section STEM to characterize the levels of cation mixing, the resulting LiNi0.9Mn0.1O2 after treated at 780 °C (denoted as NM91–780) shows a lower degree of cation mixing compared to other samples (NM91–720 and NM91–840). As a proof-of-concept application in LIBs, the NM91–780 exhibits remarkable cycling stability with 92.4% capacity retention after 100 cycles, along with excellent rate capability of 132.5 mAh g−1 at 10 C. In situ XRD analysis shows that the low cation mixing of NM91–780 inhibits harmful volumetric strain during the electrochemical process, providing structural and chemical stability for its long-term cycling. This investigation contributes to the advancement of commercializing cobalt-free high-nickel layered oxide LiNi0.9Mn0.1O2 for use in LIBs.

Phytic-Acid-Modified Copper Foil as a Current Collector for Lithium-Ion Batteries

Electrolytic copper foil is ideal for use in the anode current collectors of lithium-ion batteries (LIBs) because of its abundant reserves, good electrical conductivity, and soft texture. However, electrolytic copper foil is prone to corrosion in electrolytes and weak bonding to the anode substance. Surface modification of copper foil is considered an effective method of improving the overall electrochemical performance of LIBs. In this study, a 5 nm thickness phytic acid (PA)-based film is constructed on electrolytic copper foil using a fast electrodeposition process (about 10 s). PA-treated copper foil (PA-Cu) displays an improved corrosion resistance in electrolytes because of a strong complexation between the PA and copper. It is found that PA-treated copper foil also bonds better with graphite particles compared with pristine copper foil. LIBs with PA-Cu foils as their current collectors exhibit enhanced cycling stability, improved capacity retention, and superior rate performance at both low and high current densities. Our study offers a novel avenue for the development of high-performance electrode current collector materials for LIBs.

Bio-based anode material production for lithium–ion batteries through catalytic graphitization of biochar: the deployment of hybrid catalysts

Producing sustainable anode materials for lithium-ion batteries (LIBs) through catalytic graphitization of renewable biomass has gained significant attention. However, the technology is in its early stages due to the bio-graphite's comparatively low electrochemical performance in LIBs. This study aims to develop a process for producing LIB anode materials using a hybrid catalyst to enhance battery performance, along with readily available market biochar as the raw material. Results indicate that a trimetallic hybrid catalyst (Ni, Fe, and Mn in a 1:1:1 ratio) is superior to single or bimetallic catalysts in converting biochar to bio-graphite. The bio-graphite produced under this catalyst exhibits an 89.28% degree of graphitization and a 73.95% conversion rate. High-resolution transmission electron microscopy (HRTEM) reveals the dissolution–precipitation mechanism involved in catalytic graphitization. Electrochemical performance evaluation showed that the trimetallic hybrid catalyst yielded bio-graphite with better electrochemical performances than those obtained through single or bimetallic hybrid catalysts, including a good reversible capacity of about 293 mAh g−1 at a current density of 20 mA/g and a stable cycle performance with a capacity retention of over 98% after 100 cycles. This study proves the synergistic efficacy of different metals in catalytic graphitization, impacting both graphite crystalline structure and electrochemical performance.

Hierarchical self‐assembly of tannic acid/diethylenetriamine on polypropylene for high‐performance separator

AbstractIn lithium‐ion batteries (LIBs), separator is used to provide a barrier between the anode and cathode and provide freedom for the transport of lithium‐ions, which serves a key function in inhibiting internal short circuit and improving the battery safety. The limited wettability of commercial polyolefin separators in electrolytes restricts its utilization in extreme environmental conditions. In our work, we choose polypropylene (PP) as the precursor and can address the issue of poor wettability through suitable modification methods. Tannic acid (TA) and diethylenetriamine (DETA) were utilized to coat PP separator via hierarchical self‐assembly approach, and the coating is further stabilized by taking advantage of the specific oxidizing properties of sodium periodate. This method scarcely increases the separator thickness or sacrifices the microporous structure of the original separator. The improved separator not only exhibits outstanding wetting capability and relatively high ion conductivity (1.24 mS cm−1), but also has the highest lithium‐ion migration number of 0.74. This indicates that when the modified separator is applied to LIBs, its electrochemical performance is significantly enhanced. The enhancement in electrochemical performance of LIBs is attributed to the strong absorption and retention ability of the coating on the separator. The reversible capacity of Li/PP‐TD2 separator/LiFePO4 battery is 144.3 mAh g−1 at 2C, which is higher than that of PP separator (117.1 mAh g−1) under the same current density. Even after 200 cycles, the PP‐TD2 separator with two‐layer assembly modification still maintains a higher coulombic efficiency of 97.55% and a discharge capacity of 96.6%. This hierarchical self‐assembly modification of PP provides an effective approach for fabricating high‐performance separator.

Borate-containing triblock copolymer electrolytes for improved lithium-ion transference number and interface stability

The electrolytes with high lithium-ion transference number (tLi+) can reduce the formation of concentration polarization during charge/discharge process and improve the electrochemical performance of lithium-ion batteries (LIBs). Herein, we report triblock copolymer electrolytes (PBOEE) containing borate. The sp2 hybridized boron atoms acting as Lewis acids can anchor the anions of lithium salts, enabling PBOEE to achieve high tLi+ of up to 0.53. Also, the borate groups can promote the formation of stable organic-rich solid electrolyte interphase (SEI) film, which enables the Li symmetric cell to cycle stably at 0.1 mA cm−2/0.1 mAh cm−2 for more than 3100 h with a low overpotential of 0.08 V under 50 °C. The optimized PBOEE_24 has an ionic conductivity of 1.41 × 10−4 S cm−1 and electrochemical stability window of 4.8 V vs. Li+/Li at 50 °C. Combining these advantages, the LiFePO4/PBOEE_24/Li cell exhibits an initial discharge specific capacity of 157.3 mA h g−1 at 0.5C with a capacity retention of 85 % after 600 cycles under 50 °C. At a higher current density of 1C, the discharge capacity maintains at 128.0 mA h g−1 after 400 cycles with a capacity retention of 84.88 %. These results suggest that block copolymer containing sp2 hybridized boron atoms is a promising all-solid-state polymer electrolyte.

Carbonized polyacrylonitrile-coated three-dimensional porous TiP2O7 as a high-rate capability anode for lithium-ion batteries

TiP2O7 is a hopeful anode material for lithium-ion batteries (LIBs) due to its three-dimensional (3D) open skeletons, excellent ion transfer kinetics, and good structural stability. However, the inferior intrinsic electronic conductivity degrades seriously the electrochemical performance of LIBs. Herein, a strategy of carbonized polyacrylonitrile-coated TiP2O7 (TPO/cPAN) with 3D porous structures was proposed to enhance Li+-storage capability. The TPO/cPAN modified with 30 wt% polyacrylonitrile and calcined at 800 ℃ delivers superior long-term cycling stability at 0.5 A g−1 and excellent rate capacities of 558.7, 523.8, 477.5, 409.8, and 303.4 mAh g−1 at 0.1, 0.2, 0.4, 0.8, and 1.6 A g−1, respectively. Structural characterizations and electrochemical analysis reveal that the pyrolytic N-doped carbon layer markedly ameliorates the electron transferability and protects the electrode from organic electrolyte erosion. Meanwhile, the design of 3D porous structures and the generation of rich oxygen defects facilitate Li+ transport and pseudocapacitance energy storage. The work provides a novel pathway for optimizing the electron/ion migration of polyanionic electrode materials.

Electrospun organically modified sepiolite/PVDF coating on polypropylene separator to improve electrochemical performance of lithium-ion battery

Electrospun organically modified sepiolite/PVDF coating on polypropylene separator to improve electrochemical performance of lithium-ion battery

4-Fluorobenzyl cyanide, a sterically-hindered solvent expediting interfacial kinetics in lithium-ion batteries.

The electrochemical performance of lithium-ion batteries (LIBs) is plagued by sluggish interfacial kinetics. Fortunately, the Li+ solvation structure bridges the bulk electrolyte and interfacial chemistry, providing a pathway for promoting electrochemical kinetics in LIBs. Herein, we improve the interfacial kinetics by tuning the Li+ coordination chemistry based on solvent molecular engineering. Specifically, 4-fluorobenzyl cyanide (FBCN), featuring steric hindrance and a weak Lewis basic center, is designed to construct a bulky coordination structure with Li+, weakening ion-dipole interaction (Li+-solvents) but promoting coulombic attraction (Li+-anions) at a normal Li salt concentration. This sterically-controlled solvation chemistry reduces the interfacial barrier and thus contributes to improved rate performance, as demonstrated practically in LiFePO4//graphite pouch cells. This study provides fresh insights into solvent steric control and coordination chemistry engineering, opening a new avenue for enhancing electrochemical kinetics in LIBs.

Doped Micron Silicon and Mxene Based Composite Anodes for High-Performance Li-Ion Batteries

With the world's energy needs constantly increasing, renewable energy sources must be technologically advanced and integrated with energy storage devices to ensure their uninterrupted operation. In recent decades, researchers have devoted substantial efforts to improve the energy density of lithium-ion batteries (LIBs) [1]. While graphite remains the commercial anode in LIBs, it’s very low theoretical capacity (372 mAh g-1) restricts its use in high-energy applications. Silicon (Si), owing to its high theoretical capacity of 4200 mAh g-1, natural abundance, and appropriate Li uptake potential (0.4 V vs Li/Li+), is a promising anode material [2]. However, its massive volume expansion restricts its practical use.In this study, micron-sized Si particles are combined with graphite. Micron Si is less expensive, and the synthesis process is simpler. The well-ground mixture (Si-G) is mixed with a polymer solution to generate pyrolytic carbon (upon carbonising). This aids in the buffering of mechanical stresses caused by Si volume expansion. Furthermore, direct exposure of Si to the electrolyte is avoided, stabilising the solid electrolyte interphase (SEI). The addition of a dopant improves the intrinsic conductivity of the material, resulting in increased capacity by providing electron and Li-ion transport channels. To further enhance the composite's performance, synthesized Mxene is added to promote the charge transport between micron Si. Using various techniques such as SEM-EDAX, XRD, Raman, and XPS spectroscopy, the composite's morphology and structure is studied which reveals uniformly distributed Si, C, and Mxene sheets that retain the sheet architecture.As an anode, the composite exhibits outstanding electrochemical performance which was evident by its impressive lithium storage specific capacity of 2003 mAh g-1 (based on weight of Si) even after long term cycling (at 1C rate). Additionally, the composite demonstrates superior rate performance with a specific capacity of 2439 mAh g-1 at 10 C rate, highlighting its potential for high-power applications. Moreover, the electrode displayed a low charge transfer impedance and fast electron transport, which improved the electrochemical performance. The reason for this improved performance is the unique structure consisting of Mxene and doping, which significantly increased the Li ion diffusion and the active sites. Also, low-cost micron Si is used which has a high tap density. Thus, this work provides an approach to develop high-capacity LIBs based on silicon. Keywords: Lithium-ion battery, micron silicon anode, Mxene, doping. References Liu, L. Kang, J. Hu, E. Jung, J. Zhang, S.C. Jun, Y. Yamauchi, Unlocking the Potential of Oxygen-Deficient Copper-Doped Co 3 O 4 Nanocrystals Confined in Carbon as an Advanced Electrode for Flexible Solid-State Supercapacitors, ACS Energy Lett. 6 (2021) 3011–3019. https://doi.org/10.1021/acsenergylett.1c01373.Zhou, Y. Liu, C. Du, Y. Ren, T. Mu, P. Zuo, G. Yin, Y. Ma, X. Cheng, Y. Gao, Polyaniline-encapsulated silicon on three-dimensional carbon nanotubes foam with enhanced electrochemical performance for lithium-ion batteries, Journal of Power Sources. 381 (2018) 156–163. https://doi.org/10.1016/j.jpowsour.2018.02.009.

(Keynote) Interplay of Aging Temperature and Thermophysical Properties of Lithium-Ion Battery Electrodes

While it is well known that the electrochemical performance of lithium-ion batteries degrades with repeated cycling, the impact of aging on thermal properties is less well understood. Degradation of thermal transport within the cell can lead to increased or even excessive temperatures that in turn lead to accelerated ageing or even thermal runaway. Thus, understanding how aging impacts thermal properties is critical to ensuring safe and reliable operation of batteries. In this presentation, we evaluate the evolution of the thermal diffusivity, heat capacity, and density of the electrodes of lithium-ion battery cells which were aged at different thermal conditions. From the measured properties, we estimate the thermal conductivity of the electrodes and the active materials in the electrodes as well. Overall, the transport properties approximately follow a trend with the time-averaged temperature during the aging process. The changes in the thermal properties are correlated with observations of changes to the microstructure of the electrodes during cycling. These results can impact the design of battery systems for improved performance and stability throughout their lifetime.

Electrochemical performance of lithium-ion batteries with two-layer gradient electrode architectures

Thick electrodes whose active materials have high areal density may improve the energy densities of lithium-ion batteries. However, the weakened rate abilities and cycle lifetimes of such electrodes significantly limit their practical applications. In this study, a modified two-dimensional model was built to evaluate the influence of the electrode structure on the lithiation process. Gradient electrodes with different particle sizes along the thickness direction are designed and fabricated via a two-layer coating process. The gradient design in the thickness direction is confirmed by three-dimensional digital microscopy, energy-dispersive spectroscopy, X-ray diffraction, and scanning electron microscopy. Galvanostatic charge/discharge cycling tests and electrochemical impedance spectroscopy are performed to investigate the electrochemical properties of the fabricated gradient electrodes. The simulation results indicate that the gradient electrode structure can enhance the utilization of electrode particles on the current collector side and alleviate the nonuniformity of the solid-phase Li concentration along the thickness direction. High electrochemical performance and long-term cycling stability of the designed gradient electrodes are verified by electrochemical test. The gradient structure fabricated via multi-layer coating processes can be used to improve the electrochemical performance of thick electrodes.

A First-Principles Study of Anion Doping in LiFePO4 Cathode Materials for Li-Ion Batteries.

Doping anions into LiFePO4 can improve the electrochemical performance of lithium-ion batteries. In this study, structures, electronic properties and Li-ion migration of anion (F- , Cl- , and S2- ) doping into LiFePO4 were systematically investigated by means of density functional theory calculations. Anion substitution for oxygen atoms leads to an expansion of the LiFePO4 lattice, significantly facilitating Li-ion diffusion. For Cl- and F- anion doped into LiFePO4 , the energy barrier of Li-ion migration gets lowered to 0.209 eV and 0.283 eV from 0.572 eV. The introduction of anions narrows the forbidden band of LiFePO4 , enhancing its electronic conductivity. This work pays a way towards the rational design of high-performance lithium-ion batteries.

Synthesis of nanoscale LiCoPO4/C between few-layer graphene and its influence on electrochemical performance for lithium-ion batteries

In this study, the composite cathode material of LiCoPO4/C and graphene is synthesized using solvothermal method assisted by oleylamine. The effect of graphene addition on the material properties is fully investigated, and the synergistic effect of amorphous carbon and graphene is also studied. Graphene serves as a conductive skeleton and provides abundant diffusion paths for electrons. The nanoscale LiCoPO4 material synthesized by solvothermal method is evenly distributed around the few-layer graphene with the assistance of oleylamine, and the amorphous carbon formed after the pyrolysis of oleylamine at high temperature tightly connects LiCoPO4 to the graphene, which improves the conductivity and electrochemical performance of the sample. The results of characterization reveal that adding graphene can prepare LiCoPO4 materials with good crystallization and improve the specific surface area and pore size of the material. At the same time, the amorphous carbon and graphene inside the material also show a good degree of graphitization. Electrochemical test results show that doping graphene with a mass ratio of 6% can enhance the electrochemical performance and cycle stability of LCPC-6%G sample. The initial discharge capacity of LCPC-6%G sample reaches 157.2 mA h g−1 at 0.1 C. In this study, nanoscale LiCoPO4 samples are successfully synthesized on the surface of graphene, which provides a new idea for the preparation of nanoelectrode materials and conductive skeleton composite samples.

WS2 nanosheets vertically grown on Ti3C2 as superior anodes for lithium-ion batteries

Tungsten disulfide (WS2) is considered as a promising anode material for high-performance lithium-ion batteries (LIBs) result from its inherent characteristics such as high theoretical capacity, large interlayer spacing and weak interlayer Van der Waals force. Nevertheless, WS2 has the drawbacks of easy agglomeration, severe volume expansion and high Li+ migration barrier, which lead to rapid capacity degradation and imperfect rate ability. In this work, a novel two-dimensional (2D) hierarchical composite (Ti3C2/WS2) consisting of WS2 nanosheets vertically grown on titanium carbide (Ti3C2) nanosheets is prepared. Thanks to this distinctive hierarchical structure and synergy between WS2 and Ti3C2, the Ti3C2/WS2 composite demonstrates exceptional electrochemical performance in LIBs. In addition, we investigate the effect of the mass proportion of WS2 in Ti3C2/WS2 composite on the electrochemical performance, and find that the optimal mass ratio of WS2 is 60%. As expected, the optimal electrode exhibits a high specific capacity (650 mAh/g at 0.1 A/g after 100 cycles) and ultra-long cycle stability (400 mAh/g at 1.0 A/g after 5000 cycles).