Three-Dimensionally Ordered Macroporous Al-Doped Linio2 as a High-Rate and High-Stability Cathode for Lithium-Ion Batteries

LiNiO2 (LNO) based positive electrodes are considered as one of the most promising alternatives for electric vehicles (EVs). To meet the stringed requirements for the EVs, LNO rate capability must be improved and for this, Li-ion transport is an important factor. However, most studies focus on improving only the stability of LNO. In this work, a “morphological-chemical” dual modification strategy is proposed to synthesize a porous three-dimensionally (3D) Al-doped LNO material. The 3D structure (morphological strategy) is obtained via polystyrene (PS) template assisted synthesis, which forms an open framework ensuring faster Li-ion transport and better electrolyte permeation in the positive electrode structure consequently improving the LNO rate capability. Simultaneously, the Al-doping (chemical strategy) reduces the cation mixing degree and LNO polarization, which improves the cyclability. As a result, the 3D Al-LNO achieves 152 mAh · g-1 at 10 C compared to 120 mAh · g-1 for the non-modified LNO. The capacity retention after 80 cycles at 100 mA · g-1 increases from 76.1 % for the non-modified LNO to 87.7 % for the 3D Al-LNO at a wide working voltage window of 2.5 to 4.5 V