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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)3 research 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−1 at 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. [ABSTRACT FROM AUTHOR]

Sodium‐ion batteries (SIBs) work similarly to lithium‐ion batteries, but they cost less and are safer. However, the battery has some shortcomings, such as low energy density and poor stability, which hinder its development and application. The development of electrode materials with low cost and high‐performance characteristics is a hot and difficult point in the research of SIBs. In this paper, the existing sodium ion cathode and anode materials are systematically reviewed. Firstly, the electrochemical structures and properties of various cathode and anode materials were introduced, and the limitations of cathode and anode materials of SIBs were analyzed. Based this, the current modification methods were summarized, such as surface coating of materials, doping of heteroatoms and metal elements to improve the electrochemical performance. In this paper, the research progress and modification measures of SIBs are summarized and prospected. It is helpful to further improve its comprehensive performance and lay a foundation for the future application of cathode and anode materials for SIBs. [ABSTRACT FROM AUTHOR]

A facile and highly efficient method was proposed for the separation and regeneration of LiFePO4 (LFP) cathode materials from spent lithium‐ion batteries (LIBs). The optimal separation conditions involved immersing the spent LFP materials in NaOH (0.5 mol/L) solutions at a temperature of 90 °C, with a solid‐liquid ratio of 30 g/L under stirring of 500 rpm. The high separation effect can be attributed to the synergistic action of several factors at the interface. Furthermore, the structure, composition, morphology, and electrochemical performance of the regenerated LFP (D‐LFP) materials at different temperatures were systematically investigated. Notably, the D‐LFP material generated through calcination at 650 °C for 10 h exhibited a initial discharge capacity of 154.4 mAh g−1 at 0.5 C and the capacity retention rate of 97.3 % after 100 cycles. Moreover, a detailed investigation of the kinetics of the separation and regeneration processes was carried out, along with an exploration of the underlying electrochemical mechanism. This idea not only mitigates the harmful impact of waste on both human health and the environment but also realizes the transformation of waste into valuable resource treasure, promoting a greener and more sustainable development of society. [ABSTRACT FROM AUTHOR]

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−1 at 0.1C), high rate performance (101 mAh g−1 at 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. [ABSTRACT FROM AUTHOR]

The oxygen vacancy modulated LiTiOPO4‐y was synthesized by simple hydrothermal and high‐temperature solid‐phase methods. X‐ray diffraction (XRD) test data analyses reveal that the density of oxygen defects in LiTiOPO4‐y can be affected by the hydrothermal reaction time. The electron paramagnetic resonance (EPR) showed signal peaks at g=2.003, which proved that oxygen defects were generated. X‐ray photoelectron spectroscopy (XPS) further demonstrated that oxygen defects exist in LiTiOPO4‐y, which led to the partial conversion of Ti4+ to Ti3+. The capacity of LiTiOPO4 was limited (less than 161 mAh g−1) by cycling potential range (0.5–3.0 V). The oxygen‐deficient LiTiOPO4‐y was used to enhance lithium‐ion storage performance by mediating voltage from 0.01 to 3.0 V. The initial capacity of oxygen‐deficient LiTiOPO4‐y, which was synthesized after hydrothermal treatment for 18 h, with an exposed (121) face, reached 563.5 mAh g−1 at the current density of 500 mA g−1. After 1500 cycles, the specific discharge capacity kept at 397.2 mAh g−1. In the oxygen‐defective LiTiOPO4‐y, multiple coordination unsaturated sites are exposed, which can not only significantly enhance ion diffusion and charge transfer, but also promote Li+ to more storage sites. [ABSTRACT FROM AUTHOR]

Oxygen‐deficient TiP2O7‐y is synthesized by solvothermal and high‐temperature solid‐phase methods. X‐ray powder diffraction (XRD) test data analyses reveal that the solvothermal reaction time can affect the density of oxygen defects in the TiP2O7‐y. Fourier transform infrared spectra (FT‐IR) shows that there is a blue shift in the P−O bond because of the presence of oxygen vacancies. It is strongly demonstrated that oxygen vacancies exist in TiP2O7‐y because electron paramagnetic resonance (EPR) shows sharp peaks at g=2.003. Oxygen vacancy modulated TiP2O7‐y with exposed (541) face shows long cycling stability and super high‐rate capabilities. The initial discharge capacity of TiP2O7‐y, which was prepared after solvothermal reaction for 18 h, reached 828.4 mAh g−1. It can still maintain 246.9 mAh g−1, at 0.5 A g−1, after 500 cycles. Even cycled at 5 A g−1, the reversible rate capacity was maintained at 209.7 mAh g−1. Oxygen vacancies can not only improve the electronic conductivity of TiP2O7‐y but also increase the lithium‐ion diffusion rate. [ABSTRACT FROM AUTHOR]