Electrochemical Performance Of TiO₂-Based Hierarchical Architecture By A Directional Design

In order to overcome the above-mentioned issues,a serious of nanostructured electrode materials were fabricated and applied in the LIB/SIBs anode to further improve the rate capability and cycling performance,the specific work mainly includes the following aspects1.Hexagonal hollow mesoporous TiO₂/carbon composite as an advanced anode material for lithium-ion batteries.Exploring the fast-charge anodes is crucial to meet the needs of lithium ion battery?LIB?markets.Here,a hexagonal hollow mesoporous TiO₂/Carbon composite?HHM-TiO₂/C?was synthesized by a template-engaged approach.The obtained HHM-TiO₂/C exhibits superior rate capability and long-life cycing stability when used as anode materials in Li-ion batteries,with a specific capacity over 200 mAh g^-1 after 500 cycles at a current density of 1 C.Even at a high rate of 20 C,the current density reaches to 4 A g^-1,a high capacity of 130 mAh g^-1 still can be maintained.The excellent performance is attributed to the engineered structure can not only effectively shorten the diffusion of Li⁺and electron to enhance the conductivity,but also can buffer the pulverization and aggregation of electrode and thus maintain the structural integrity during the charge/discharge process.2.Towards long-life and high rate sodium ion batteries by engineered pseudocapacitive sodium storage based on ultrafine TiO₂-carbon microstructure.The sluggish kinetics and low power density is the highly concerned issues and need significantly to be overcome for achieving high performance sodium ion batteries.Here,a sandwich-type 3D porous structure constructed by the interconnected 2D N,P-codoped carbon sheets with the composite of TiO₂ nanoparticles embedded in carbon matrix,is proposed to tune the redox reaction occurring on the surface or near-surface of the active material,promoting the capacitive behavior and enhancing electrochemical performance.The unique porous structure with large specific surface and structural stability is capable of facilitating ion/electron transportation and providing more active sites to adsorb more Na⁺,while the ultrafine TiO₂ nanoparticles could accommodate the stress change accompanying volume expansion and contribute to reduce the Na⁺diffusion length.Thanks to these structural merits,the composite electrode demonstrate a superior cycling stability over 5000 cycles without obvious capacity fading,as well as an excellent rate capability of 87 mAh g^-1 at high current density of 10A g^-1.The kinetic analysis demonstrated the enhanced surfaced pseudocapacitive behavior benefitting from the structure design and ultra-small nanoparticles,is the main force to acquire the outstanding performance.