Rational design of covalent organic frameworks with high capacity and stability as a lithium-ion battery cathode

A two-dimensional covalent organic framework (NTCDI-COF) with rich redox active sites, high stability and crystallinity was designed and prepared. As a cathode material for lithium-ion batteries (LIBs), NTCDI-COF exhibits excellent electrochemical performance with an outstanding discharge capacity of 210 mA h g^-1 at 0.1 A g^-1 and high capacity retention of 125 mA h g^-1 after 1500 cycles at 2 A g^-1. A two-step Li⁺ insertion/extraction mechanism is proposed based on the ex situ characterization and density functional theory calculation. The constructed NTCDI-COF//graphite full cells can realize a good electrochemical performance.