LiNi 0.8 Co 0.15 Al 0.05 O 2 (LNCA) cathode materials have an extremely high energy density, which can greatly enhance the driving range of pure electric vehicles if they are used in onboard batteries. However, the development of the LNCA cathode material is restricted by the expensive transition metal cobalt (Co). Therefore, researchers are devoted to finding other metals to replace Co to synthesize nickel (Ni)-rich Co-free materials to reduce the cost. To investigate the feasibility of replacing Co with manganese (Mn) as a transition metal, this paper reports the synthesis and compares the properties of four Ni-rich materials with different Co−Mn contents by gradually adding Mn to LNCA materials and reducing the Co content in equal amounts using an oxalic acid coprecipitation method. The results show that Mn can compensate the effect of Co deficiency to a certain extent; it is feasible to use Mn to completely replace Co in the synthesis of Nirich ternary Co-free materials under the premise of sacrificing a certain initial specific capacity. The tetrameric material LiNi 0.8 Co 0.1 Mn 0.05 Al 0.05 O 2 substituted with trace amounts of Mn exhibited the most excellent electrochemical properties among the four synthesized materials. Therefore, to synthesize satisfactory Ni-rich Co-free materials, it is suggested to develop and synthesize quaternary Co-free materials on the basis of LiNi 0.

Nickel-rich layered materials are the most commercially valuable power battery materials. However, because of the existence of Ni3+, lattice deterioration of nickel-rich ternary materials is especially serious in the cycle process. In this experiment, LiNi0.8–x Co0.1+x Mn0.1O2 is prepared by increasing the content of cobalt (x = 0.02, 0.04, 0.06). Through electrochemical test, X-ray diffraction analysis, galvanostatic intermittent titration technique, Rietveld refinement analysis, and other characterization methods, the effect of cobalt content enhancement on the nickel-rich layered materials is explained. With the increase of cobalt content, the adverse phase transition of 4.2 V is inhibited, and the material shows preferable stability during cycling. Incredibly and encouragingly, the samples with increasing cobalt content show superior performance of cycle and rate, less redox inhomogeneity and impedance, and also higher initial Coulomb efficiency. According to these results, the nickel-rich high cobalt layered material LiNi0.82Co0.12Mn0.06O2 was synthesized, which showed excellent performance. This research proves the complex and indispensable role of cobalt and provides a cobalt-rich strategy for the design of nickel-rich layered materials.

A series of carbon-coated LiMn1−xFexPO4 (x = 0, 0.1, 0.2, 0.3, 0.4) materials are successfully constructed using glucose as carbon sources via sol-gel processes. The morphology of the synthesized material particles are more regular and particle sizes are more homogeneous. The carbon-coated LiMn0.8Fe0.2PO4 material obtains the discharge specific capacity of 152.5 mAh·g−1 at 0.1 C rate and its discharge specific capacity reaches 95.7 mAh·g−1 at 5 C rate. Iron doping offers a viable way to improve the electronic conductivity and lattice defects of materials, as well as improving transmission kinetics, thereby improving the rate performance and cycle performance of materials, which is an effective method to promote the electrical properties.

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