Dual-type confinement strategy: Improving the stability of organic composite cathodes for Lithium-ion batteries with longer lifespan

Abstract

Inclusive reports on organic cathodes are the key evidence of their superior performance for Lithium-ion batteries. However, it is still promising to simultaneously achieve a higher practical specific capacity and longer cycling life, owing to the crucial concern of the dissolution of active molecules in organic electrolytes. The introduction of porous carbon confinement and coating which can impart discharge capacity and cycling stability, is highly beneficial. Herein, we designed and prepared a novel composite cathode (designated as HKUST-1-C@DHAQ@TiO2) with small molecules (DHAQ) in porous carbon skeleton (HKUST-1-C) as core and TiO2 as shell. The unique dual-type confinement strategy offers short Li+/e- diffusion directions for redox reactions and superior structural stability during cycling without dissolution or decomposition of the components, resulting in excellent electrochemical performance. The HKUST-1-C@DHAQ@TiO2 cathode delivers significant specific capacity (209 mAh g−1, 0.1 A g−1), markable Coulombic efficiency (nearly 100 %), notable cycling stability (86 % retention for provided 200 cycles) and excellent rate capacity (138 mAh g−1 at 1.0 A g−1). The presented findings offer the deep understanding of redox reactions and organic cathode evolution mechanisms for the progress of smarter energy storage batteries.