Improving the electrochemical performance of Li-rich Li<Subscript>1.2</Subscript>Ni<Subscript>0.13</Subscript>Co<Subscript>0.13</Subscript>Mn<Subscript>0.54</Subscript>O<Subscript>2</Subscript> cathode material by LiF coating

To suppress the capacity fade of Li-rich Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ material as cathode materials for lithium-ion battery, we introduce a LiF coating layer on the surface to improve the cycling performance of Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ material. The modified sample shows a capacity of 163.2 mAh g^?1 with a capacity retention of 95% after 100 cycles at a current density of 250 mA g^?1, while the pristine sample only delivers a capacity of 129.9 mAh g^?1 with a capacity retention of 82%. Compared with the pristine material, the LiF-modified sample exhibits an obvious enhancement in the electrochemical performance, which will be very beneficial for this material to be commercialized on the new energy vehicles and other related areas.     

Synthesis and electrochemical properties of Li<Subscript>1.2</Subscript>Mn<Subscript>0.54</Subscript>Ni<Subscript>0.13</Subscript>Co<Subscript>0.13</Subscript>O<Subscript>2</Subscript> cathode material for lithium-ion battery

The layered Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ lithium-rich manganese-based solid solution cathode material has been synthesized by a simple solid-state method. The as-prepared material has a typical layered structure with R-3m and C2/m space group. The synthesized Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ has an irregular shape with the size range from 200 to 500 nm, and the primary particle of Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ has regular sphere morphology with a diameter of 320 nm. Electrochemical performances also have been investigated. The results show that the cathode material Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ prepared at 900 °C for 12 h has a good electrochemical performance, which can deliver a high initial discharge capacity of 233.5, 214.2, 199.3, and 168.1 mAh g^?1 at 0.1, 0.2, 0.5, and 1 C, respectively. After 50 cycles, the capacity retains 178.0, 166.3, 162.1, and 155.9 mAh g^?1 at 0.1, 0.2, 0.5, and 1 C, respectively. The results indicate that the simple method has a great potential in synthesizing manganese-based cathode materials for Li-ion batteries.     

Effects of doping Al on the structure and electrochemical performances of Li[Li<Subscript>0.2</Subscript>Mn<Subscript>0.54</Subscript>Ni<Subscript>0.13</Subscript>Co<Subscript>0.13</Subscript>]O<Subscript>2</Subscript> cathode materials

The Li-rich cathode material Li[Li_0.2Mn_0.54Ni_0.13Co_0.13]O₂ had been successfully synthesized by a carbonate coprecipitation method. The effects of substituting traces of Al element for different transitional metal elements on the crystal structure and surface morphology had been investigated by X-ray diffraction (XRD) and field emission scanning electron microscopy. The results revealed that all the materials showed similar XRD patterns and surface morphology. It was demonstrated that LNCMAl1 exhibited the superior electrochemical performance. The discharge capacity was 265.2 mAh g^?1 at 0.1 C and still maintained a discharge capacity of 135.6 mAh g^?1 at 5.0 C. The capacity retention could still be 58.2 and 66.8% after 50 cycles at 1.0 and 2.0 C, respectively. Electrochemical impedance spectra results proved that the remarkably improved rate capability and cycling performance could be ascribed to the low charge transfer resistance and enhanced reaction kinetics.     

Preparation of carbon encapsulated Li<Subscript>4</Subscript>Ti<Subscript>5</Subscript>O<Subscript>12</Subscript> anode material for lithium ion battery through pre-coating method

Carbon encapsulated Li₄Ti₅O₁₂ (C/Li₄Ti₅O₁₂) anode material for lithium ion battery was prepared by using the pre-coat method of two steps, and the TiO₂ was pre coated before the reaction with Li₂CO₃. The structure and morphology of the resultant C/Li₄Ti₅O₁₂ materials were characterized by X-ray diffraction (XRD) and scanning microscopy (SEM). Electrochemical tests showed that at 0.1 C, the initial discharge capacity was 169.9 mAh g^?1, and the discharge capacity was 80 mAh g^?1 at 5 C. After 100 cycles at 2 C, the discharge specific capacity was 108.5 mAh g^?1. Compare with one step coating method, results showed the C/Li₄Ti₅O₁₂ prepared by pre-coat method can reduce the particle’s size and effectively improve the electrochemical performance.     

Improved electrochemical properties of YF<Subscript>3</Subscript>-coated Li<Subscript>1.2</Subscript>Mn<Subscript>0.54</Subscript>Ni<Subscript>0.13</Subscript>Co<Subscript>0.13</Subscript>O<Subscript>2</Subscript> as cathode for Li-ion batteries

Yttrium fluoride YF₃ layer with different coating contents is successfully covered on the surface of Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ via a common wet chemical approach. The XRD, SEM, TEM, and charge-discharge tests are applied to investigate the influence of YF₃ layer on the micro-structural, morphology, and electrochemical properties of Li_1.2Mn_0.54Ni_0.13Co_0.13O₂. And the electrochemical test results demonstrate that the YF₃-coated LMNCO samples exhibit the improved electrochemical properties. The 2wt.%YF₃-coated LMNCO delivers a discharge capacity of 116.6 mAh g^?1 at 5 C rate, much larger than that (95.6 mAh g^?1) of the pristine one. Besides, the electrochemical impedance spectroscopy (EIS) and cyclic voltammetric results indicate that the YF₃ coating layer can promote the optimization formation of SEI film and reversibility of the electrochemical redox.     

CeO<Subscript>2</Subscript> coating to improve the performance of Li[Li<Subscript>0.2</Subscript>Mn<Subscript>0.54</Subscript>Ni<Subscript>0.13</Subscript>Co<Subscript>0.13</Subscript>]O<Subscript>2</Subscript>

The Li[Li_0.2Mn_0.54Ni_0.13Co_0.13]O₂ coated with CeO₂ has been fabricated by an ionic interfusion method. Both the bare and the CeO₂-coated samples have a typical layered structure with R-3m and C2/m space group. The results of XRD and TEM images display that the CeO₂ coating layer on the precursor could enhance the growth of electrochemically active surface planes ((010), (110), and (100) planes) in the following ionic interfusion process. The results of galvanostatic cycling tests demonstrate that the CeO₂-coated sample has a discharge capacity of 261.81 mAh g^?1 with an increased initial Coulombic efficiency from 62.4 to 69.1% at 0.05 °C compared with that of bare sample and delivers an improved capacity retention from 71.7 to 83.4% after 100 cycles at 1 °C (1 °C?=?250 mA g^?1). The results of electrochemical performances confirm that the surface modification sample exhibits less capacity fading, lower voltage decay, and less polarization.     

Nano Li<Subscript>4</Subscript>Ti<Subscript>5</Subscript>O<Subscript>12</Subscript> as sulfur host for high-performance Li-S battery

S/Li₄Ti₅O₁₂ cathode with high lithium ionic conductivity was prepared for Li-S battery. Herein, nano Li₄Ti₅O₁₂ is used as sulfur host and fast Li⁺ conductor, which can adsorb effectively polysulfides and improve remarkably Li⁺ diffusion coefficient in sulfur cathode. At 0.5 C, S/Li₄Ti₅O₁₂ cathode has a stable discharge capacity of 616 mAh g^?1 at the 700th cycle and a capacity loss per cycle of 0.0196% from the second to the 700th cycle, but the corresponding values of S/C cathode are 437 mAh g^?1 and 0.0598%. Even at 2 C, the capacity loss per cycle of S/Li₄Ti₅O₁₂ cathode is only 0.0273% from the second to the 700th cycle. The results indicate that Li₄Ti₅O₁₂ as the sulfur host plays a key role on the high performance of Li-S battery due to reducing the shuttle effect and enhancing lithium ionic conductivity.     

Fabrication and electrochemical investigation of Li<Subscript>0.5</Subscript>TiO<Subscript>2</Subscript> as anode materials for lithium ion batteries

Hexagonal and cubic Li_0.5TiO₂ particles have been fabricated through magnesiothermic reduction of Li₂TiO₃ particles in a temperature range of 600 to 640 °C. The prolonged reduction time results in lattice transition from hexagonal to cubic structure of Li_0.5TiO₂. Their microstructures, valance state, chemical composition, as well as electrochemical performance as anode candidates for lithium ion batteries have been characterized and evaluated. The hexagonal Li_0.5TiO₂ exhibits better electrochemical activity compared with the cubic one. Further, the carbon-coated hexagonal Li_0.5TiO₂ displays improved electrochemical performance with initial reversible capacity of 176.6 mAh g^?1 and excellent cyclic behavior except capacity fading in the initial 10 cycles, which demonstrate a novel anode candidate for long lifetime lithium ion batteries.     

Urea-assisted solvothermal synthesis of monodisperse multiporous hierarchical micro/nanostructured ZnCo<Subscript>2</Subscript>O<Subscript>4</Subscript> microspheres and their lithium storage properties

High-quality monodisperse multiporous hierarchical micro/nanostructured ZnCo₂O₄ microspheres have been fabricated by calcinating the Zn_1/3Co_2/3CO₃ precursor prepared by urea-assisted solvothermal method. The as-prepared products are characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), and Brunauer-Emmett-Teller (BET) measurement to study the crystal phase and morphology. When tested as anode material for lithium ion batteries, the multiporous ZnCo₂O₄ microspheres exhibit an initial discharge capacity of 1,369 mAh g^?1 (3,244.5 F cm^?3) and retain stable capacity of 800 mAh g^?1 (1,896 F cm^?3) after 30 cycles. It should be noted that the good electrochemical performances can be attributed to the porous structure composed of interconnected nanoscale particles, which can promote electrolyte diffusion and reduce volume change during discharge/charge processes. More importantly, this ZnCo₂O₄ 3D hierarchical structures provide a large number of active surface position for Li⁺ diffusion, which may contribute to the improved electrochemical performance towards lithium storage.     

Nitrogen-doped carbon nanofiber decorated LiFePO<Subscript>4</Subscript> composites with superior performance for lithium-ion batteries

Nitrogen-doped carbon nanofiber (NCNF) decorated LiFePO₄ (LFP) composites are synthesized via an in situ hydrothermal growth method. Electrochemical performance results show that the embedded NCNF can improve electron and ion transfer, thereby resulting in excellent cycling performance. The as-prepared LFP and NCNF composites exhibit excellent electrochemical properties with discharge capacities of 188.9 mAh g^?1 (at 0.2 C) maintained at 167.9 mAh g^?1 even after 200 charge/discharge cycles. The electrode also presents a good rate capability of 10 C and a reversible specific capacity as high as 95.7 mAh g^?1. LFP composites are a potential alternative high-performing anode material for lithium ion batteries.     

Electrospinning preparation of one-dimensional Co<Superscript>2+</Superscript>-doped Li<Subscript>4</Subscript>Ti<Subscript>5</Subscript>O<Subscript>12</Subscript> nanofibers for high-performance lithium ion battery

One-dimensional Co²⁺-doped Li₄Ti₅O₁₂ nanofibers with a diameter of approximately 500 nm have been synthesized via a one-step controllable electrospinning method. The Co²⁺-doped Li₄Ti₅O₁₂ nanofibers were systematically characterized by XRD, ICP, TEM, SEM, BET, EDS mapping, and XPS. Based on the cubic spinel structure and one-dimensional effect of Li₄Ti₅O₁₂, Co²⁺-doped Li₄Ti₅O₁₂ nanofibers exhibit the enlarged lattice volume, reduced particle size and enhanced electrical conductivity. More importantly, Co²⁺-doped Li₄Ti₅O₁₂ nanofibers as a lithium ion battery anode electrode performs superior electrochemical performance than undoped Li₄Ti₅O₁₂ electrode in terms of electrochemical measurements. Particularly, the reversible capacity of Co²⁺-doped Li₄Ti₅O₁₂ electrode reaches up to 140.1 mAh g^?1 and still maintains 136.5 mAh g^?1 after 200 cycles at a current rate of 5 C. Therefore, one-dimensional Co²⁺-doped Li₄Ti₅O₁₂ nanofiber electrodes, showing high reversible capacity and remarkable recycling property, could be a potential candidate as an anode material.     

Synthesis of spinel LiNi<Subscript>0.5</Subscript>Mn<Subscript>1.5</Subscript>O<Subscript>4</Subscript> as advanced cathode via a modified oxalate co-precipitation method

Spinel-type LiNi_0.5Mn_1.5O₄ (LNMO) cathode materials for lithium ion batteries have been synthesized via a modified oxalate co-precipitation method. By virtue of the co-precipitation of Li⁺ with transition metal ions, the target materials can be obtained through one-pot reaction without subsequent mixing with lithium salts. What’s more, a uniform distribution between the lithium and transition metal ions at molecular level could be realized, which is beneficial for final electrochemical performances. The physical and electrochemical properties of the material are characterized by XRD, TGA, EDS, FT-IR, SEM, CV, EIS, and charge/discharge tests. The results prove that the as-prepared material owns a cubic spinel structure with a space group of Fd-3m, high crystallinity, uniform particle size, and excellent electrochemical performances. A higher initial capacity and superior rate performance are delivered compared with that of material by conventional co-precipitation method. High capacities of 131.7 and 104.0 mAh g^?1 could be displayed at 0.5 and 10 C, respectively. Excellent cycle stability is also demonstrated with more than 98.5 % capacity retention after 100 cycles at 1 C.     

Surface-modified Li[Li<Subscript>0.2</Subscript>Mn<Subscript>0.54</Subscript>Ni<Subscript>0.13</Subscript>Co<Subscript>0.13</Subscript>]O<Subscript>2</Subscript> nanoparticles with LaF<Subscript>3</Subscript> as cathode for Li-ion battery

The LaF₃-coated Li[Li_0.2Mn_0.54Ni_0.13Co_0.13]O₂ nanoparticles were synthesized via co-precipitation method followed by simple chemical deposition process. The crystal structure, particle morphology, and electrochemical properties of the bare and coated materials were studied by XRD, SEM, TEM, charge–discharge tests. The results showed that the surface coating on Li[Li_0.2Mn_0.54Ni_0.13Co_0.13]O₂ nanoparticles were amorphous LaF₃ layer with a thickness of about 10–30 nm. After the surface modification with LaF₃ films, the coating layer served as a protective layer to suppress the side reaction between the positive electrode and electrolyte, and the Li[Li_0.2Mn_0.54Ni_0.13Co_0.13]O₂ oxide demonstrated the improved electrochemical properties. The LaF₃-coated Li[Li_0.2Mn_0.54Ni_0.13Co_0.13]O₂ electrode delivered the capacities of 270.5, 247.9, 197.1, 170.0, 142.7, and 109.5 mAh g^?1 at current rates of 0.1, 0.2, 0.5, 1, 2, and 5 C rate, respectively. Besides, the capacity retention was increased from 85.1 to 94.8 % after 100 cycles at 0.5 C rate. It implied surface modification with LaF₃ played an important role to improve the cyclic stability and rate capacity of the Li-rich nickel manganese oxides.     

Electrochemical comparison of LiFe<Subscript>0.4</Subscript>Mn<Subscript>0.595</Subscript>Cr<Subscript>0.005</Subscript>PO<Subscript>4</Subscript>/C and LiMnPO<Subscript>4</Subscript>/C cathode materials

A comparison of electrochemical performance between LiFe_0.4Mn_0.595Cr_0.005PO₄/C and LiMnPO₄/C cathode materials was conducted in this paper. The cathode samples were synthesized by a nano-milling-assisted solid-state process using caramel as carbon sources. The prepared samples were investigated by XRD, SEM, TEM, energy-dispersive X-ray spectroscopy (EDAX), powder conductivity test (PCT), carbon-sulfur analysis, electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge cycling. The results showed that LiFe_0.4Mn_0.595Cr_0.005PO₄/C exhibited high specific capacity and high energy density. The initial discharge capacity of LiFe_0.4Mn_0.595Cr_0.005PO₄/C was 163.6 mAh g^?1 at 0.1C (1C = 160 mA g^?1), compared to 112.3 mAh g^?1 for LiMnPO₄/C. Moreover, the Fe/Cr-substituted sample showed good cycle stability and rate performance. The capacity retention of LiFe_0.4Mn_0.595Cr_0.005PO₄/C was 98.84 % over 100 charge-discharge cycles, while it was only 86.64 % for the pristine LiMnPO₄/C. These results indicated that Fe/Cr substitution enhanced the electronic conductivity for the prepared sample and facilitated the Li⁺ diffusion in the structure. Furthermore, LiFe_0.4Mn_0.595Cr_0.005PO₄/C composite presented high energy density (606 Wh kg^?1) and high power density (574 W kg^?1), thus suggested great potential application in lithium ion batteries (LIBs).     

Nanocrystalline Li<Subscript>2</Subscript>TiO<Subscript>3</Subscript> electrodes for supercapattery application

Nanocrystalline Li₂TiO₃ was successfully synthesized using solid-state reaction method. The microstructural and electrochemical properties of the prepared material are systematically characterized. The X-ray diffraction pattern of the prepared material exhibits predominant (002) orientation related to the monoclinic structure with C2/c space group. HRTEM images and SAED analysis reveal the well-developed nanostructured particles with average size of ～40 nm. The electrochemical properties of the prepared sample are carried out using cyclic voltammetry (CV) and chronopotentiometry (CP) using Pt//Li₂TiO₃ cell in 1 mol L^?1 Li₂SO₄ aqueous electrolyte. The Li₂TiO₃ electrode exhibits a specific discharge capacity of 122 mAh g^?1; it can be used as anode in Li battery within the potential window 0.0–1.0 V, while investigated as a supercapacitor electrode, it delivers a specific capacitance of 317 F g^?1 at a current density of 1 mA g^?1 within the potential range ?0.4 to +0.4 V. The demonstration of both anodic and supercapacitor behavior concludes that the nanocrystalline Li₂TiO₃ is a suitable electrode material for supercapattery application.     

Preparation and characterization of Li1.2Ni0.13Co0.13Mn0.54O2 cathode materials for lithium-ion battery

Lithium-rich cathode materials Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ with (sample SF) and without (sample SP) formamide was synthesized by a spray-dry method. The crystalline structure and particle morphology of as-prepared materials were characterized by X-ray diffraction and scanning electron microscope. The specific surface area (SSA) of the Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ prepared from different routes was determined by a five-point Brunauer–Emmett–Teller (BET) method using N₂ as absorbate gas. Being compared with the material synthesized without spray-drying process (sample CP), sample SP has much higher SSA. The additive formamide is helpful to form regular and solid precursor particles in spray-drying process, which results in a slightly aggregation of grains and reduction of SSA for sample SF. The electrochemical activities of the materials are closely related to their morphology and SSA. In the voltage range of 2–4.8 V at 25 °C, sample SP present a discharge capacity of 257 mAh g^?1 at 0.1 C rate and 170 mAh g^?1 at 1 C rate. The sample CP delivered only 136 mAh g^?1 when discharged at 1 C rate. The elevated specific capacity and rate capability are attributed to smaller primary particle and higher SSA. Both cycle performance and rate capability of Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ were improved when formamide was used in spray-dry process. Discharge capacity of SF is 140.5 mAh g^?1 at 2 C rate, and that of SP is 132.3 mAh g^?1. Overlarge SSA of SP may provoke serious side reaction, so that its electrochemical performance was deteriorated.     

LiNi<Subscript>0.5</Subscript>Mn<Subscript>1.5</Subscript>O<Subscript>4</Subscript> hollow nano-micro hierarchical microspheres as advanced cathode for lithium ion batteries

The high-voltage spinel-type LiNi_0.5Mn_1.5O₄ (LNMO) is a promising cathode material for next-generation lithium ion batteries. In this study, hollow LNMO microspheres have been synthesized via co-precipitation method accompanied with high-temperature calcinations. The physical and electrochemical properties of the materials are characterized by x-ray diffraction (XRD), TGA, RAMAN, CV, scanning electron microscope (SEM), transmission electon microscopy (TEM), electrochemical impendence spectroscopy (EIS), and charge-discharge tests. The results prove that the microspheres combine hollow structures inward and own a cubic spinel structure with space group of Fd-3m, high crystallinity, and excellent electrochemical performances. With the short Li⁺ diffusion length and hollow structure, the hierarchical LNMO microspheres exhibit 138.2 and 108.5 mAh g^?1 at 0.5 and 10 C, respectively. Excellent cycle stability is also demonstrated with more than 98.8 and 88.2 % capacity retention after 100 cycles at 1 and 10 C, respectively.     

The formation and electrochemical property of lithium-excess cathode material Li<Subscript>1.2</Subscript>Ni<Subscript>0.13</Subscript>Co<Subscript>0.13</Subscript>Mn<Subscript>0.54</Subscript>O<Subscript>2</Subscript> with petal-like nanoplate microstructure

Lithium-excess oxide shows great potential for its high specific capacity of exceeding 280 mAh g^?1. However, the poor rate capability caused by the poor electrochemical kinetics condition as well as the structure instability block the way of its application. Here, we aimed to improve the kinetics circumstance for lithium ion transference through the material bulk by synthesizing lithium-excess oxide with high specific surface area. Petal-like nanoplates and nanoparticles with excellent electrochemical performance were obtained at different sintering temperatures and times by the electrospinning-sintering method, which facilitates the sufficient contact of electrode and electrolyte and helps to reduce the polarization during the electrochemical reaction process. Cyclic voltammetry tests verify that a portion of oxidized oxygen is reduced reversibly at 3.0 V and the reduction of oxygen contributes to the discharge capacity. Electrochemical impedance spectroscopy plots illustrate the ameliorative electrochemical kinetics is conductive to the oxidation of oxygen at 4.5 V.     

Facial synthesis of carbon-coated ZnFe<Subscript>2</Subscript>O<Subscript>4</Subscript>/graphene and their enhanced lithium storage properties

Carbon-coated ZnFe₂O₄ spheres with sizes of ~110–180 nm anchored on graphene nanosheets (ZF@C/G) are successfully prepared and applied as anode materials for lithium ion batteries (LIBs). The obtained ZF@C/G presents an initial discharge capacity of 1235 mAh g^?1 and maintains a reversible capacity of 775 mAh g^?1 after 150 cycles at a current density of 500 mA g^?1. After being tested at 2 A g^?1 for 700 cycles, the capacity still retains 617 mAh g^?1. The enhanced electrochemical performances can be attributed to the synergetic role of graphene and uniform carbon coating (~3–6 nm), which can inhibit the volume expansion, prevent the pulverization/aggregation upon prolonged cycling, and facilitate the electron transfer between carbon-coated ZnFe₂O₄ spheres. The electrochemical results suggest that the synthesized ZF@C/G nanostructures are promising electrode materials for high-performance lithium ion batteries.

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Graphical abstract ?

     

Elevated electrochemical property of LiMn<Subscript>2</Subscript>O<Subscript>4</Subscript> originated from nano-sized Mn<Subscript>3</Subscript>O<Subscript>4</Subscript>

By employment of nano-sized pre-prepared Mn₃O₄ as precursor, LiMn₂O₄ particles have been successfully prepared by facile solid state method and sol-gel route, respectively. And the reaction mechanism of the used precursors of Mn₃O₄ is studied. The structure, morphology, and element distribution of the as-synthesized LiMn₂O₄ samples are characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Compared with LiMn₂O₄ synthesized by facile solid state method (SS-LMO), LiMn₂O₄ synthesized by modified sol-gel route (SG-LMO) possesses higher crystallinity, smaller average particle size (~175 nm), higher lithium chemical diffusion coefficient (1.17 × 10^?11 cm² s^?1), as well as superior electrochemical performance. For example, the cell based on SG-LMO can deliver a capacity of 85.5 mAh g^?1 at a high rate of 5 °C, and manifests 88.3% capacity retention after 100 cycles at 0.5 °C when cycling at 45 °C. The good electrochemical performance of the cell based on SG-LMO is ascribed mainly to its small particle size, high degree of dispersion, and uniform element distribution in bulk material. In addition, the lower polarization potential accelerates Li⁺ ion migration, and the lower atom location confused degree maintains integrity of crystal structure, both of which can effectively improve the rate capability and cyclability of SG-LMO.