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In this work, nanorod lithium iron phosphate (LiFePO₄) materials are synthesized by a liquid-phase method using iron powder, H₃PO₄, and LiOH$\cdot$H₂O as source materials. The crystal structure, morphology and electrochemical performance are characterized. The results illustrate that the molar ratio of Li:Fe:P plays a significant role in regulating the morphology and structure of LiFePO₄. When the molar ratio is Li:Fe:P $=$ 3:1:1 it shows irregular nanoparticles, and when the molar ratio is Li:Fe:P $=$ 3:1:1.5 it transforms into rod-like particles. Furtherly, The LiFePO₄/C (Li:Fe:P $=$ 3:1:1.5) material, adding carbon coating at 180${}^{\circ }$C for 12h, displays a discharge capacity of 120mAh/g at 1C, and even after 200 cycles with the capacity retention of above 95.7%. Our findings provide a simple, economical and environmentally friendly way to produce LiFePO₄ cathode material for outstanding performance in lithium-ion battery (LIB).

${\mathrm{\text{LiFePO}}}_4/\mathrm{\text{C}}$ samples were obtained via high-temperature ball milling route with different mixing processes. Ultrasonic radiation and wet mechanical agitation were used as mixing processes, respectively. The effects of different mixing processes on the structure and electrochemical performance of ${\mathrm{\text{LiFePO}}}_4/\mathrm{\text{C}}$ were investigated. The results exhibited that ${\mathrm{\text{LiFePO}}}_4/\mathrm{\text{C}}$ prepared by high-temperature ball milling with ultrasonic irradiation as mixing processes displayed the best rate capability and cycle stability among all the samples: it delivered discharge capacities of $151\pm 2$ (0.1 C), $112\pm 2$ (5.0 C) and $99\pm 2$ (10 C) ${\mathrm{\text{mAh g}}}^{-1}$, respectively. The discharge capacity was $136\pm 2$${\mathrm{\text{mAh g}}}^{-1}$ at 0.5 C-rate over 100 cycles with capacity retention of 95.0%. It is concluded that ultrasonic irradiation is an effective mixing process for the preparation of ${\mathrm{\text{LiFePO}}}_4$ cathode material via high-temperature ball milling route.

The application of lithium iron phosphate (LiFePO₄) was still hindered by its poor high rate performance. Surface coating had proven to be an effective strategy to solve these problems. However, the previous surface coating method made the synthesis process more complicated. In this work, a simple organic salt decomposition method was developed to prepare LiFePO₄@Ni cathode material (LFP@Ni). Scanning electron microscope (SEM), X-ray diffractometer (XRD) energy disperse spectroscopy (EDS) confirmed that a uniform nickel-coated composite structure had been successfully constructed without changing the crystal structure. The charge and discharge test showed that after 200 cycles at 5C, LFP@Ni maintained a discharge specific capacity of 65.02% and the exchange current density was 1.3 times that of LFP. Compared with LFP and LFP-Ni, the composite cathode LFP@Ni had better cycle capacity. This improvement was attributed to the good conductivity of nickel, which can quickly conduct electrons in the LFP cathode material, thereby improving the dynamic performance of the LFP cathode material.

LiFePO₄ cathode materials were prepared by a solid-state method followed by one-step heat treatment. To improve the electrochemical properties of the LiFePO₄, acetylene black (AB), citric acid (CA), and pyrene are added as carbon source, respectively. The cyclic voltammetry (CV), AC impedance and galvanostatic charge/discharge testing results showed that using the LiFePO₄-C composite such as the AB carbon source exhibits higher discharge capacity and stability than the other composite. Synthesized LiFePO₄-C/Li cells (with AB) showed that initial discharge capacity was 140.65 mA h g^-1 and at the 2nd cycle were 145.87 mA h g^-1, respectively. Morphology and electrochemical performance of the LiFePO₄ cathode materials were investigated. Furthermore, the cell was subjected to current density studies (0.1 mA cm^-2) that suggested excellent capacity retention of the cell at 25°C.

The monodispersed LiFe${{}_{1-}}_x$M${}_x$PO₄/C [$x$$\approx$ 0.0040; $M$ = Mn${}^{2+}$, Co${}^{2+}$, Ni${}^{2+}$, Cu${}^{2+}$, Zn${}^{2+}$] nanocomposites obtained by LiFePO₄ modified with binuclear metal aminophthalocyanines (M₂(PcTa)₂O and M₂(PcTa)₂C(CF${}_3{)}_2)$ are utilized as positive electrode materials for lithium ion batteries. The preparation method for these nanocomposites is a controllable solvothermal method using a mixture of ethylene glycol and $N$,$N$-dimethylformamide as the solvent. The microstructure and electrochemical properties of the different nanocomposites are discussed and compared. The results show that the LiFePO₄ samples modified with M₂(PcTa)₂C(CF${}_3{)}_2$can improve the initial discharge specific capacity of the lithium ion battery up to 154.2 mAh.g${}^{-1}$at the rate of 0.1 C, and 93.5% of the initial discharge capacity could be retained after 50 cycles. This research shows that the proposed process can enhance the electrochemical performance of high power LiFePO₄ for lithium ion batteries.

The results of simple and environmental-friendly method of the carbon nanocoatings on low-conductive cathode material have been shown in this work. The carbon nanocoatings were prepared during wet impregnation process of precursor derived from hydrophilic polymer based on poly($N$-vinylformamide) modified by pyromellitic acid. The crystal structures and morphology of all composites were characterized by X-ray powder diffraction (XRD), low temperature nitrogen adsorption/desorption measurements (N₂-BET) and transmission electronic microscopy (TEM). The electrical properties of the obtained composites were examined by EC studies. The electrochemical performance was carried out in galvanostatic mode with stable charge–discharge current and performed in Li/Li${}^{+}$/(CCL/LiFePO${}_4)$ type cells. The process of formation CCL/LiFePO₄ nanocomposite significantly enhances the electrical conductivity of the material and improves its capacity retention and electrochemical performance.

A novel low cost Na${}^{+}$/Li${}^{+}$ hybrid electrolyte was proposed for hybrid supercapacitor. By partly substituting Lithium salt with Sodium salt, the Li${}^{+}$/Na${}^{+}$ hybrid electrolyte exhibits synergic advantages of both Li${}^{+}$ and Na${}^{+}$ electrolytes. Our findings could also be applied to other hybrid power sources.

Wet grinding is one of the most common forms of technology in powder production and preparation. Sand mill is the latest technology of wet grinding, which can effectively reduce the grinding particle size and improve the powder reactivity. LiFePO₄ is one of the widely used cathode materials for lithium batteries at present, and the grinding process will affect the product performance. In this paper, parallel type and series type grinding processes were simulated by the single-cylinder system and the double cylinder system, which were studied and compared through the preparation of LiFePO₄. It was discovered that the series type grinding process can not only increase the grinding efficiency but also improve the consistency of particle size distribution. LiFePO₄ prepared by the series type grinding process has better rate performance and a higher discharge voltage platform. Attributing to the uniform particle size of LiFePO₄, the lithium-ion diffusion coefficient was raised, which was proved by the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). To sum up, based on the results of this paper, the properties of lithium iron phosphate will be affected by the particle size distribution, which is related to the grinding process. Therefore, in order to obtain the best performance of LiFePO₄, it is necessary to choose the appropriate production process. This research work provides references and the basis for the research of powder grinding production technology.