Search

Polyanionic cathode materials are increasingly used in research because of their good cycling performance, high theoretical capacity, and high operating voltage. However, it exhibits poor performance due to its structure, which prevents it from reaching its full theoretical capacity. In this study, carbon‐coated Li6V3(PO4)5@C cathode materials are constructed under Li3V2(PO4)3research conditions using the sol–gel process and anhydrous citric acid as the carbon source. Several boron doping concentrations are investigated to create Li6V3(PO4)5@BC cathode materials. The electrochemical measurements demonstrate that during the first cycle, at a current density of 0.5 C and a B doping quantity of 2 wt%, the specific discharge capacity of Li6V3(PO4)5@BC reaches 167.43 mAh g−1. The steady discharge specific capacity following 80 cycles of constant‐current charging and discharging is 136.84 mAh g−1. Li6V3(PO4)5@BC‐2 has a specific discharge capacity of 131.1 mAh g−1at 2 C. The material's electrochemical performance greatly improves following the right quantity of B doping, which is primarily attributed to the increase in carbon layer defects brought on by B's entrance. This can increase the rate of lithium‐ion migration and hold more lithium ions. The Li6V3(PO4)5@BC‐2 cathode material prepared by the sol‐gel method exhibits a high initial discharge specific capacity of 167.43 mAh g−1at 0.5 C .

LiTiOPO4 was prepared by solid-phase combustion method using citric acid as fuel. The LiTiOPO4 materials were characterized by X-ray diffraction test (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM). The XRD test showed that the synthesized samples were pure phases and the addition of different weight fractions of the combustion agent citric acid did not change the phase structure of the LiTiOPO4. The microscopic observations revealed that the LiTiOPO4 prepared after the addition of citric acid as a combustion agent was a sheet-like stacked structure. The electrochemical test results showed that the rate discharge capacity of LiTiOPO4 anode at 5000 mA g−1 maintains 184.7 mAh g−1 in the voltage range of 0.01–3.0 V and keeps at 147.2 mAh g−1 after 500 cycles. The LiTiOPO4 anode exhibits excellent cycling stability and good reversibility, which is attributed to the high crystallinity of LiTiOPO4 prepared by solid-phase combustion and the lamellar stacked layer structure that facilitates lithium-ion insertion/de-insertion.

Nanoparticle Na3V2(PO4)3/C materials with different polyacrylonitrile contents can be successfully synthesized using precipitation method. As an energy storage material used in the production of lithium batteries which is also compared with pure of that, the Na3V2(PO4)3/C not only has a larger capacity, but also has a very high cycle stability. In particular, the initial discharge capacities of the Na3V2(PO4)3/C sample annealed at 750°C containing 10 wt% of polyacrylonitrile are 130.9 and 122.2 mAh g−1at current densities of 0.5 and 1 C, respectively; the corresponding coulomb efficiencies are 97.3 and 99.5%. It is also worth noting that the capacity retention can reach as high as 92.7% for 500 cycles at 1 C.

Herein, a facile method with high efficiency is proposed for the separation and regeneration of LiMn2O4(LMO) cathode material for spent lithium‐ion batteries through a simple heat treatment method. At first, the aluminum foil is separated at 450 °C in air, with a separation efficiency as high as 97.95%. Then, separation LMO is regenerated with high crystallinity at 650 °C with an optimum calcination time of 6 h. Importantly, this method allows D‐LMO to exhibit high reversible capacity (133 mAh g−1at 0.1C), high rate performance (101 mAh g−1at 5C), and long lifespan (0.5C, 92.1% capacity retention ratio after 100 cycles). A positive effect of the pyrolysis of polyvinylidene fluoride on D‐LMO is also suggested by the results. Moreover, a detailed investigation of the kinetics of the separation and regeneration is done, and the electrochemical mechanism is explored. Furthermore, this method requires much less energy input and chemical consumption, which would be helpful for environmental protection and green recycling. A facile green method with high efficiency is proposed for the separation and regeneration of LiMn2O4cathode material for spent lithium‐ion batteries through a simple heat treatment method.

Due to the high theoretical capacity, high platform voltage, stable structure, and mild conditions for synthesis, LiVOPO4 is expected to become the next generation of cathode materials for lithium-ion batteries (LIBs). However, due to the relatively weak ionic conductivity, its commercial application has been largely limited. The paper reported that acetylene black was used as the reducing agent and the pure phase nanostructured orthorhombic β-LiVOPO4 was obtained by carbothermal reduction method. A significant improvement in ionic conductivity was achieved, and the results were compared with previous studies, the initial discharge capacity of the material was considerably enhanced. The results show that the electrical conductivity and the initial discharge capacity of the material were also significantly improved. The sample obtained by holding at 600 °C for 10 h exhibited a maximum discharge capacity of 141.4 mAh g−1 between 3 V and 4.5 V at 0.05 C, with a value of 136.3 mAh g−1, retained after 50 cycles. This represents capacity retention of 96.39%.