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We use a facile high-temperature solid-phase method to coat a layer of Ni-rich ternary material (LiNi 0.8 Co 0.1 Mn 0.1 O 2) on the surface of lithium iron phosphate. This active coating greatly improves the intrinsic conductivity of LiFePO 4. Compared to the conventional carbon material cladding, since this cladding layer is electrochemically active, the problem of decreasing the proportion of active material due to the addition of a cladding layer can be avoided to a certain extent. Compared with the samples capped with conventional organic carbon source (151.2 mAh g−1) and inorganic carbon source (155.9 mAh g−1) at 0.2 C, the discharge specific capacity was as high as 165.7 mAh g−1. Capacity retention after 200 cycles is up to 98 %, which is much higher than that of glucose and graphene oxide (GO)-coated samples (95.9 %, 96.6 %). Even when charging and discharging cycles are performed at different multipliers (2C and 10C), the retention rate remains higher than the latter. [ABSTRACT FROM AUTHOR]

We successfully prepare LiFePO 4 nanosheets with a primary particle linearity of only 50–80 nm with the {010} facet as the main exposed surface by using the mixed-solvent method, and control their agglomeration morphology by using ethylene glycol, diethylene glycol, and triethylene glycol (EG, DEG, and TEG) as the inducing agents, which solves the problem of the irregular agglomeration of the nanoparticles to a large extent. The obtained secondary particles have regular morphology, consistent particle size, staggered stacking between nanosheets, and the resulting stacked pores greatly increase the active sites of the material. In addition, due to the different molecular structures of the inducer of LiFePO 4 chelating degree of deviation, as a way to achieve the purpose of controlling the thickness of the carbon layer on the surface of LiFePO 4. The discharge specific capacity of the spiny spherical secondary particles prepared with EG can reach 168.5 mAh g−1 at 0.2 C, which is close to its theoretical capacity. Due to the nano effect of primary particles, the material is in full contact with the electrolyte and exhibits successively 149.8, 125.9 and 114.5 mAh g−1 even at high multiplicities (2 C, 5 C, 10 C). • The linearity of the primary particles of the prepared material is only 50-80 nm. • Primary particles prepared with the (010) surface as the main exposed surface. • Control of nanoparticle agglomeration morphology by inducers. • The LFP@EG exhibited high specific capacitance and good cycling stability. [ABSTRACT FROM AUTHOR]

It has always been an important research direction for improving the intrinsic conductivity of Lithium iron phosphate materials. Doping can not only improve the intrinsic conductivity but also induce lattice distortion to increase the diffusion rate of lithium ions to improve the electrochemical performance. Zn-doped LiFe 1-x Zn x PO 4 (x = 0, 0.025, 0.05, 0.075) is prepared from LiOH·H 2 O, FeSO 4 ·7H 2 O, H 3 PO 4 , ZnSO 4 ·7H 2 O. The composition, structure, morphology and electrochemical performance of the material are characterized in detail by XRD, SEM, EDS, cyclic voltammetry test, AC impedance test and other methods. The results show that the nano-spherical LiFe 0.075 Zn 0.025 PO 4 exhibits excellent capacity performance and rate performance without intentionally coating C. The initial discharge specific capacity of the positive electrode material is 153.6 mAh·g−1 at 0.2C. The material also exhibits excellent cycle performance, with a discharge-specific capacity of 148.6mAh g−1 and a capacity retention rate of 96.7% after 100 cycles at a current density of 0.2C. Compared with the undoped samples, the doped ZnSO 4 improves the actual capacitance of the samples. The high specific capacity retention rate at large rate charge-discharge indicates that zinc doping improves the structural stability of the samples. The crystal structure is not significantly damaged during the large current charge discharge process, and the magnification performance is improved. • Select zinc, the last element of the fourth period transition group, and make full use of its characteristics of small ionic radius and high charge density between ions. Make some bond energy strengthening, further stabilize the frame, improve the material cycle stability. • By one-step hydrothermal method, zinc salt with excellent water solubility is selected for doping, so that the raw materials can be mixed at atomic level, and the problem of uneven doping is solved. • Through the synergistic effect of adding CTAB and doping elements, the agglomeration and uneven particle size of nanoparticles are greatly improved. • The selected method is simple, the experimental repeatability is high, and the raw materials are easy to obtain. [ABSTRACT FROM AUTHOR]