Dual conductive surface engineering of Li-Rich oxides cathode for superior high-energy-density Li-Ion batteries

Li-rich (LR) layered oxide cathode for high-energy-density Li-ion batteries are receiving considerable attention. However, their intrinsic issues hinder the implementation of LR in simultaneously achieving higher energy and power densities. Herein, a dual-conductive surface control strategy is proposed. This surface layer contains an electronic conductive carbon nanotube (CNT) skeleton and an ionic conductive heteroepitaxial spinel structure, which endows the LR with the light-weight and self-standing characteristic. As evidenced by prolonged electrochemical and structural evolution, this surface layer can reduce polarization, restrain structural distortion and facilitate fast electronic/ionic diffusion. Density functional theory (DFT) calculations demonstrate a higher electron conductivity with a narrower band gap across the CNT/LR interface than that of pure LR, and reveal a highly connective Li+ percolation network and reduced Li+ migration energies for the layered-spinel heterogeneous interface. The designed LR cathode presents a high energy density (1077 Wh kg−1 at 0.1 C), excellent rate capability (195 mAh g−1 at 10 C) and superior cycle stability. When utilized as an additive-free cathode for high-voltage full-battery, impressive energy density (645 Wh kg−1 based on the cathode and anode) and ultra-long cycle life (maintaining 87% capacity after 400 cycles) can be achieved. These results and this dual-conductive surface control strategy provide an exciting perspective and avenue for the further development of high-performance electrode material.