Covalent triazine-based framework incorporating keto-enol tautomerization as modified separator for boosting the performance of lithium-sulfur batteries

The modified separator is an effective way to inhibit the shuttle effect of polysulfide, and improve the performance of lithium-sulfur battery (LSB). Herein, a triazine-based COF incorporating keto-enamine form (TAPTTFP-COF) was prepared and used as modified separator in high-performance LSB. The LSB with TAPT-TFP-COF modified separator exhibited excellent discharge specific capacity and good long-term stability. Consequently, the LSB used TAPT-TFP-COF decorated separator displayed a high reversible capacity at 0.1 C of 1283 mA h g- 1, and a high specific capacity of 837 mA h g- 1 even when the current density increased to 2 C. The assembled LSB exhibited fine cyclic performance at 1 C remained 748 mA h g- 1 after 600 cycles with an average capacity decay rate of 0.036 % per cycle. TAPT-TFP-COF improved membrane can significantly restrain the shuttle of poly- sulfides, improve the cycle stability and higher rate performance, providing another strategy for the construction of separator in high-performance LSB.