A novel morphology-controlled synthesis of Na+-doped Li- and Mn-rich cathodes by the self-assembly of amphiphilic spherical micelles

The fundamental challenges in the commercialization of Liand Mn-rich (LMR) cathode materials are the terrible capacity retention and detrimental voltage fading due to the degradation and collapse of the electrode material structure during prolonged cycles. Morphologically controlled synthesis of LMRs and ions doping are recognized as the most significant strategies to solve the above problems. Herein, we present a simple and versatile morphology-controlled method for the synthesis of Na+-doped Li1.2Ni0.13Co0.13Mn0.54O2 with a 3D porous skeleton-supported core and hierarchical structure by the self-assembly of amphiphilic spherical micelles for the first time. Benefitting from the synergy between structural design and Na+-doping, the samples demonstrate excellent cycling stability and rate performance that retains 190.8 mAh g(-1) at 5C high rate. Most of all, the intrinsic mechanism of Na+ doping on promoting the rate capability and cycling stability has been clarified by the in situ XRD characterization and first principle calculations, which is ascribed to the lower diffusion barrier (about 70.5 meV) of Li+ in Na+-doped LMRs than pristine LMRs. The above viewpoint also has provided a widely applicable research approach for the modification mechanism of other doping systems. (c) 2020 Elsevier B.V. All rights reserved.