Tuning the carbon content on TiO 2 nanosheets for optimized sodium storage

Abstract

Titanium dioxide (TiO2) has been considered as a promising anode candidate for sodium ion batteries (NIBs). In this work, we report the synthesis of anatase TiO2 nanosheets coated by nitrogen doped carbon derived from dopamine precursor (TiO2@C) as high performance anode materials for NIBs applications. The carbon contents can be controlled from 2.6 wt% to 10.4 wt% by varying the polymerization time of dopamine. X-ray diffraction patterns confirm there is no phase change after carbon coating. When employed as an anode for NIBs, the TiO2@C composites exhibit improved electrochemical performances in terms of higher specific capacity and better cycling stability compared to pure TiO2 nanosheets. Notably, with a carbon content of 4.8 wt%, the TiO2@C nanosheets delivers a reversible capacity of 180 mA h g -1 and shows stable cycling performance with no discharge capacity decay from 2 nd cycle onward over 50 cycles. Even at high current density of 10 C, the capacity still remains 82 mA h g -1 . The excellent cycling stability and rate performances can be 2 ascribed to the protective effects of carbon coating layer which reserves the structure stability and enhances electrical conductivity during cycling.

Two-Dimensional Titanium Carbonitride Mxene for High-Performance Sodium Ion Batteries

“…Moreover, the cycling performance of Ti 3 CN SIBs maintained a high discharge specific capacity of 85.6 mAh g –1 after 500 cycles at 100 mA g –1 . The significantly improved capacities and long-term cycling performance of Ti 3 CN compared to those of its counterpart Ti 3 C 2 SIBs indicate that Ti 3 CN can be considered promising anode materials for sodium-based energy storage devices for their high efficiency, low cost, and the abundant resources of sodium (Na) precursors in the earth’s crust. − Many efforts have been made in the development of high-performance anode materials for SIBs, including expanded graphite, carbon, tin-based compounds, titanium oxides (NaTiO 2 and TiO 2 ), metal sulfides, phosphorus, and others. − …”

Two-dimensional nanostructures for sodium-ion battery anodes

“…[182][183][184] Enhancing the electrical conductivity of TiO2 will most likely lead to improved electrochemical performance in SIBs. [175][176][177][178][179][180][181][182][183][184][185][186][187][188][189][190] Recently, Chen et.al reported Na + intercalation pseudocapacitance in a TiO2 (consisting of 76.9% TiO2(B) and 23.1% anatase TiO2)/graphene nanocomposite, which enabled high-rate capability and long cycle life in a sodium-ion battery. 186 In their study, the hybridization of graphene with TiO2 nanocrystals provided a more feasible channel at the graphene-TiO2 interface for sodium intercalation/deintercalation with a much lower energy barrier, thus leading to fast charge storage and long-term cyclability ( Fig.…”