Li-rich layered Li1.2Mn0.54Ni0.13Co0.13O2 derived?from transition metal carbonate with a micro–nanostructure as a cathode material for high-performance Li-ion batteries

摘要

Compared to commercialized cathode materials, Li-rich layered oxide exhibits a superior mass energy density. However, owing to its low tap/press density, the advantage of its volume energy density is not as obvious as that of its mass energy density, which limits its applications in some volume-constrained fields. It has been shown that the morphology of the precursor is critical to the performances of the final product. Here, solvothermal and co-precipitation methods were adopted to synthesize transition metal carbonate balls with micro-size particles to obtain high-density Li-rich layered oxides. The solvothermal synthesized carbonate showed a micro–nano hierarchical structure composed of nanoplates as subunits, and the co-precipitated synthesized carbonate just presents a micrometer quasi-ball morphology. The Li _(1.2) Mn _(0.54) Ni _(0.13) Co _(0.13) O _(2) derived from the above solvothermal synthesized carbonate (ST-LMNCO) demonstrated an improved volume density of ～14% compared to the one derived from the co-precipitated synthesized carbonate (CP-LMNCO). As for electrochemical performances, the ST-LMNCO exhibited a higher discharge specific capacitance (296.6 mA h g ~(?1) for the first discharge), a better rate performance (201.6 mA h g ~(?1) at 1C rate) and a better capacity retention capability (86.2% after 80 cycles) than the CP-LMNCO. The morphologies of the transition metal carbonates as starting materials significantly impacted the morphologies of the derived Li _(1.2) Mn _(0.54) Ni _(0.13) Co _(0.13) O _(2) particles. Therefore, the carbonate with a hierarchical micro–nanostructure obtained from the solvothermal method is a promising precursor for high performance Li _(1.2) Mn _(0.54) Ni _(0.13) Co _(0.13) O _(2) .