Lithium polyacrylate-coated LiMn2O4 cathode materials with excellent performance for lithium ion batteries

A novel facile approach to coat LiMn 2 O 4 by lithium polyacrylate (PAALi) is demonstrated. The PAALi-coated LiMn 2 O 4 (LMO@2%PAALi) and LiMn 2 O 4 (LMO) are characterized by charge–discharge tests, X-ray diffraction (XRD), PAALi dissolving experiment, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG), and inductively coupled plasma optical emission spectrometer (ICP-OES). XRD and FTIR analyses indicate that there are no clear differences between LMO@2%PAALi and LMO. PAALi dissolving experiment indicates that PAALi is indissolvable in LiPF 6 -EC/DMC/EMC electrolyte. TEM results reveal that LiMn 2 O 4 particles are coated by PAALi. ICP-OES results indicate that this stable PAALi coating can prevent the Mn ions dissolving from active LiMn 2 O 4 materials and then the stability of LiMn 2 O 4 crystals in electrolyte are greatly enhanced. These unique features ensure that LMO@2%PAALi possesses much better rate performance, higher discharge capacity, better cycling performance, and lower charge transfer resistance over LMO. The discharge capacity of LMO@2%PAALi at 0.2 C reaches up to 127.2 mAh g −1 at room temperature.