Exploring a Co-Free, Li-Rich Layered Oxide with Low Content of Nickel as a Positive Electrode for Li-Ion Battery
Arcangelo Celeste, Mariarosaria Tuccillo, A. Santoni, P. Reale, Sergio Brutti, Laura Silvestri
Abstract
The development of cathode materials represents the key bottleneck to further push the performance of current Li-ion batteries (LIB) beyond the commercial benchmark. Li-rich transition-metal-layered oxides (LRLOs) are a promising class of materials to use as high-capacity/high-potential positive electrodes in LIBs thanks to the large lithium content (e.g., ∼1.2 Li equiv per formula unit) and the exploitation of multiple redox couples (e.g., Mn4+/3+, Co4+/3+, Ni4+/3+/2+). In this work, we propose and demonstrate experimentally a Co-free overlithiated LRLO material with a limited nickel content, i.e., Li1.25Mn0.625Ni0.125O2. This LRLO is able to exchange reversibly an outstanding practical specific capacity at room temperature, i.e., 230 mAh g–1 at C/10 for almost 200 cycles, and can sustain high current rates, i.e., 118 mAh g–1 at 2C. This material has been successfully prepared by a facile solution combustion synthesis and characterized by scanning electron microscopy (SEM), X-ray photoemission spectroscopy (XPS), X-ray absorption near-edge spectroscopy (XANES), X-ray diffraction (XRD), and Raman techniques. Overall, our positive electrodes based on Li1.25Mn0.625Ni0.125O2 overlithiated Co-free LRLO is a step forward in the development of the materials for batteries with improved performance and better environmental fingerprint.