Study on electrochemical performance and mechanism of V-doped Li2FeSiO4 cathode material for Li-ion batteries

Carbon Loaded Nano-Designed Spherically High Symmetric Lithium Iron Orthosilicate Cathode Materials for Lithium Secondary Batteries

In the present study, Li2FeSiO4 (LFS) cathode material has been prepared via a modified polyol method. The stabilizing nature of polyol solvent was greatly influenced to reduce the particle size (~50 nm) and for coating the carbon on the surface of the as-mentioned materials (~10 nm). As-prepared nano-sized Li2FeSiO4 material deliver initial discharge capacity of 186 mAh·g-1 at 1C with the coulombic efficiency of 99% and sustain up to 100 cycles with only 7 mAh·g-1 is the difference of discharge capacity from its 1st cycle to 100th cycle. The rate performance illustrates the discharge capacity 280 mAh·g-1 for lower C-rate (C/20) and 95 mAh·g-1 for higher C-rate (2C).

Novel hard carbon/graphite composites synthesized by a facile in situ anchoring method as high-performance anodes for lithium-ion batteries

In this report, novel hard carbon/graphite composites are prepared by a simple in situ particle anchoring method, followed by carbonization. The effects of loading content of hard carbon on the structure and electrochemical performance of the composites are investigated. The SEM results show that the hard carbon particles are anchored randomly on the surface of graphite. The electrochemical measurements demonstrate that an appropriate loading content of hard carbon can remarkably increase the specific reversible capacity of graphite, which is mainly contributed by lithiation in hard carbon, whereas excessive loading leads to the formation of a thick particle shell onto the surface of graphite, which deteriorates the initial coulombic efficiency drastically. Kinetic tests further show that excessive loading of hard carbon is unfavorable for lithium-ion diffusion probably due to the increased interface distance and decreased electroconductivity. The composite loaded with 10 wt% hard carbon exhibits balanced lithium storage performance with high reversible capacity of 366 mA h g-1, high initial coulombic efficiency (∼91.3%), and superior rate capability and cycling performance. Thus, in this study, we suggest a facile and effective strategy to fabricate a promising graphite anode material for high-performance lithium-ion batteries.

Multi-heteroatom doped carbon coated Na3V2(PO4)3 derived from ionic liquids

Multi-heteroatom doped carbon coated Na₃V₂(PO₄)₃ derived from an ionic liquid exhibits superior rate performance and cycling stability.

Mg doped Li2FeSiO4/C nanocomposites synthesized by the solvothermal method for lithium ion batteries

A series of porous Li₂Fe_1-xMg_xSiO₄/C (x = 0, 0.01, 0.02, 0.04) nanocomposites (LFS/C, 1Mg-LFS/C, 2Mg-LFS and 4Mg-LFS/C) have been synthesized via a solvo-thermal method using the Pluronic P123 polymer as an in situ carbon source. Rietveld refinement of the X-ray diffraction data of Li₂Fe_1-xMg_xSiO₄/C composites confirms the formation of the monoclinic P2₁ structure of Li₂FeSiO₄. The addition of Mg facilitates the growth of impurity-free Li₂FeSiO₄ with increased crystallinity and particle size. Despite having the same percentage of carbon content (∼15 wt%) in all the samples, the 1Mg-LFS/C nanocomposite delivered the highest initial discharge capacity of 278 mA h g^-1 (∼84% of the theoretical capacity) at the C/30 rate and also exhibited the best rate capability and cycle stability (94% retention after 100 charge-discharge cycles at 1C). This is attributed to its large surface area with a narrow pore size distribution and a lower charge transfer resistance with enhanced Li-ion diffusion coefficient compared to other nanocomposites.

Investigations on Zr incorporation into Li3V2(PO4)3/C cathode materials for lithium ion batteries

Zr-modified Li₃V₂(PO₄)₃/C composites (LVZrP/C and LVP/C-Zr) obtained from different ways exhibit enhanced performance, in which Zr exists not only in the LVP lattice but also on the LVP surface.

Investigation of Co-incorporated pristine and Fe-doped Li3V2(PO4)3 cathode materials for lithium-ion batteries

Co was first employed to modify Fe-doped Li₃V₂(PO₄)₃/C. Under the common effect of doping and a hybrid layer (C + CoO + FeO) coating, the as-obtained composite showed a remarkable rate capability and low capacity fading.

Vanadium-doped lithium-rich layered-structured cathode material Li1.2Ni0.2Mn0.6O2 with a high specific capacity and improved rate performance

Fine powders of Li_1.2Ni_0.2Mn_0.6−xV_xO₂ (x = 0, 0.002, 0.005, 0.01, 0.02) are prepared by a thermopolymerization method.

Unveiling the electrochemical mechanisms of Li2Fe(SO4)2 polymorphs by neutron diffraction and density functional theory calculations

The structure of electrochemically active Li_1.5Fe(SO₄)₂ with difference Fourier maps highlighting the two lithium positions, which are also represented in the unit cell.

Advances in high-capacity Li2MSiO4 (M = Mn, Fe, Co, Ni, …) cathode materials for lithium-ion batteries

This review highlights the high-capacity Li₂MSiO₄ (M = Mn, Fe, Co, Ni, …) cathode materials for lithium-ion batteries.

Synthesis and electrochemical performance of Na-modified Li2Fe0.5Mn0.5SiO4 cathode material for Li-ion batteries

Li_2−xNa_xFe_0.5Mn_0.5SiO₄/C composites have been synthesized via a refluxing-assisted solid-state reaction. They can be well indexed as two mixed polymorphs with P2₁ and Pmn2₁. Na-doping can significantly improve the capacity and the rate capability.