Modified Coprecipitation Synthesis of Mesostructure-Controlled Li-Rich Layered Oxides for Minimizing Voltage Degradation

Modified carbonate coprecipitation synthesis without addition of chelating agent is introduced to obtain mesostructure-controlled Li-rich layered oxides. The designed mesostructure for target material Li1.2Ni0.2Mn0.6O2 has uniformly dispersed spherical secondary particles with size around 3 μm. These micrometer-sized particles consist of self-assembled crystallites with size of ∼150 nm. This unique design not only decreases the surface area compared with the sample with dispersive particles, but also increases overall structural mechanical stability compared with the sample with larger dense secondary particles as observed by transmission X-ray microscope. As a result, the voltage decay and capacity loss during long-term cycling have been minimized to a large extent. Our findings clearly demonstrate that mesostructure design of Li-rich layered oxides play a key role in optimizing this class of cathode materials. Surprisingly, the voltage fading issue can be partially mitigated by such an approach.