Synthesis Of Multilayer Exfoliated Ti₃C₂T_x As Aqueous Capacity Battery Cathode Materials And Electrochemical Performance Study

Capacitor batteries as a new energy storage device with the advantages of long cycle life, environment-friendly, fast charge and discharge, can be widely used in energy storage devices. Because the energy density of aqueous battery is often low, the development of high-performance anode and cathode materials has become a hot topic at home and abroad.The stability of Ti3C2Tx alkenes with graphite-like layered structure is better and the Li+diffusion voltage is lower. So it can be used as an aqueous capacitance battery anode material. This article aims to explore the best preparation conditions for Ti3C2Tx, and the electrochemical performance of Ti3C2Txat lithium, sodium, magnesium salts. The specific contents are as follows:To optimizethe conditions for preparation of Ti3C2Tx,the different reaction time,ultrasonic time, and the influence of different reaction solvent are investigated. When the reaction time is 18h,ultrasonic time is 24 h,Ti3C2Tx produced through the HF leaching of Ti3AlC2 has a large number of layer structure of the preparation of morphology. XRD?ICP?EDS and Raman analysis shows that A1 in Ti3AlC2 has been nearly completely removed.The electrochemical tests which use the Ti3C2Tx electrode in the different sodium salts(0.5mol·dm-3 Na22SO4?lmol·dm-3NaCl and NaNO3) show that the SO42- has the least influence on the adsorption and stripping of sodium into/from Ti3C2Tx. When the current density is 50 mA·g-1, the discharge specific capacity reaches 70.2mAh·g-1. While Cl- and NO3- have great impact on the performance of the electrode. Electrodes in 0.5, 1, 1.5 mol·dm-3 Na2SO4 electrochemical test results show that Ti3C2Tx electrode has the best rate performance in 1 mol·dm-3 Na2SO4. After 500 cycles at 200mA·g-1,the discharge capacity still remains 55 mAh·g-1. When the current density is 20 mA·g-1, the discharge specific capacity of the Sodium ion capacitor battery ?-MnO2/Ti3C2Tx reaches 76.7 mAh·g-1 with the battery voltage up to 2.4 V.Through CV.CP and EIS electrochemical tests about the Ti3C2Tx electrode in the different Lithium salts(0.5mol·dm-3Li2SO4?1mol·dm-3LiCl and LiNO3) show that the SO42-has the least influence on the adsorptionvstripping of Lithium ion into/from Ti3C2Tx.When the current density is 50 mA·g-1, the discharge specific capacity reaches 98.0 mAh·g-1. Electrochemical testing results of electrode in 0.2, 0.5, 1 mol·dm-3 Li2SO4 shows that Ti3C2Tx electrode has the best rate performance in 0.5 mol·dm-3 Li2SO4.After 500 cycles at 100mA·g-1, the discharge capacity still remains 90 mAh·g-1. The capacitor battery LiMn2O4/Ti3C2Tx has better performance on capacity and stability and its battery voltage also reaches 2.4 V. When the current density is 10 mA·g-1, the discharge specific capacity reaches 103 mAh·g-1.Testing with the Ti3C2Tx electrode in the different magnesium salts(0.5mol·dm-3MgSO4?MgCl2 and Mg(NO3)2),electrode shows the best performance in MgCl2. When the current density is 50 mA·g-1, the discharge specific capacity reaches 86.3 mAh·g-1. Electrode in 0.5, 1, 2 mol·dm-3 MgCl2 electrochemical testing results shows that Ti3C2Tx electrode has the best rate performance in 1 mol·dm-3 MgCl2. After 500 cycles at 200 mA·g-1, the discharge capacity still remains 63.5 mAh·g-1 and the coulomb efficiency still remains above 100%.