Preparation And Electrochemical Performance Of Heteroatom-doped Anode Materials For Rechargeable Batteries

In this dissertation, a series of heteroatom-doped anode materials including N-doped TiO₂ nanotube/N-doped graphene composites, N-doped ordered mesoporous carbon（NCMK） and Nitrogen-phosphorous co-doped carbon microspheres（NPCM） were prepared via hydrothermal synthesis followed by heat treatment, and studied the impact of heteroatom-doping on the structure and electrochemical performance of the samples through different characterization methods and electrochemical performance tests, the main contents are as follows:For the first time, we have synthesized the N-doped TiO₂ nanotube/N-doped graphene composites via hydrothermal synthesis followed by heat treatment to study it’s electrochemical performance as the anode material in Li- ion battery. The composites were prepared using TiO₂ nanoparticles as matrix, urea as nitrogen source and a small amount of graphene as conductive grid at a high concentration of sodium hydroxide environment. The electrochemical performance showed that N-doped TiO₂ nanotube/N-doped graphene composites exhibited higher specific capacity and excellent rate performance, and the composites electrode could deliver a specific capacity of 91 mAh g-1 even at a high current density of 5A g-1.Using SBA-15 as template, sucrose as carbon source, urea as nitrogen source via a simple hydrothermal synthesis and heat treatment method, we prepared N-doped ordered mesoporous carbon（NCMK） and studied their electrochemical performance as the anode material in Na- ion battery for the first time. Compared with un-doped mesoporous carbon（CMK-3）, the NCMK electrode material showed high discharge capacity（delivered a specific capacity of 374 mAh g-1 at current density of 0.1A g-1 during the initial cycle）, good cycling performance（after 45 cycles, the electrode still delivered a discharge capacity of 327 mAh g-1 at current density of 0.1A g-1, the capacity loss of per cycle was only 1.06 mAh g-1） and excellent rate performance（delivered a specific capacity of 91 mAh g-1 at 2A g-1）.Using glucose as carbon source,（NH4）2HPO4 as nitrogen source and phosphorus source, through a simple hydrothermal reaction and subsequent heat treatment process, we have prepared the nitrogen-phosphorous co-doped carbon microspheres（NPCM） and studied its electrochemical performance as anode material in sodium ion batteries, The electrochemical performance test results showed that the NPCM exhibited high discharge capacity（delivered a specific capacity of 305 mAh g-1 at current density of 0.1A g-1 during the initial cycle）, excellent rate performance（even at a high current density of 5Ah g-1, the NPCM electrode can deliver a specific capacity of 136 mAh g-1） and good cycling stability（the capacity can retain 98 % within 200 cycles at the current density of 0.5A g-1）, exhibiting excel ent cycle life.