Carbon Nanotubes Coupled with Metal Ion Diffusion Layers Stabilize Oxide Conversion Reactions in High-Voltage Lithium-Ion Batteries
Qian Li, Yingqiang Wu, Zhaomin Wang, Hai Ming, Wenxi Wang, Dongming Yin, Limin Wang, Husam N. Alshareef, Jun Ming
Abstract
Creating new architectures combined with super diverse materials for achieving more excellent performances has attracted great attention recently. Herein, we introduce a novel dual metal (oxide) microsphere reinforced by vertically aligned carbon nanotubes (CNTs) and covered with a titanium oxide metal ion-transfer diffusion layer. The CNTs penetrate the oxide particles and buffer structural volume change while enhancing electrical conductivity. Meanwhile, the external TiO2–C shell serves as a transport pathway for mobile metal ions (e.g., Li+) and acts as a protective layer for the inner oxides by reducing the electrolyte/metal oxide interfacial area and minimizing side reactions. The proposed design is shown to significantly improve the stability and Coulombic efficiency (CE) of metal (oxide) anodes. For example, the as-prepared MnO–CNTs@TiO2–C microsphere demonstrates an extremely high capacity of 967 mA h g–1 after 200 cycles, where a CE as high as 99% is maintained. Even at a harsh rate of 5 A g–1 (ca. 5 C), a capacity of 389 mA h g–1 can be maintained for thousands of cycles. The proposed oxide anode design was combined with a nickel-rich cathode to make a full-cell battery that works at high voltage and exhibits impressive stability and life span.