Tuning the Defects of Two-Dimensional Layered Carbon/TiO2 Superlattice Composite for a Fast Lithium-Ion Storage.

Bingheng Liu,Ming Zhang,Anchang Li,Bo Gu,Zhongrong Shen,Jingxian Wang

doi:10.3390/ma15051625

Abstract

Defect engineering is one of the effective ways to improve the electrochemical property of electrode materials for lithium-ion batteries (LIB). Herein, an organic functional molecule of p-phenylenediamine is embedded into two-dimensional (2D) layered TiO2 as the electrode for LIB. Then, the 2D carbon/TiO2 composites with the tuning defects are prepared by precise control of the polymerization and carbothermal atmospheres. Low valence titanium in metal oxide and nitrogen-doped carbon nanosheets can be obtained in the carbon/TiO2 composite under a carbonization treatment atmosphere of N2/H2 gas, which can not only increase the electronic conductivity of the material but also provide sufficient electrochemical active sites, thus producing an excellent rate capability and long-term cycle stability. The prepared composite can provide a high capacity of 396.0 mAh g−1 at a current density of 0.1 A g−1 with a high capacitive capacity ratio. Moreover, a high specific capacity of 80.0 mAh g−1 with retention rate of 85% remains after 10,000 cycles at 3.0 A g−1 as well as the Coulomb efficiency close to 100%. The good rate-capability and cycle-sustainability of the layered materials are ascribed to the increase of conductivity, the lithium-ion transport channel, and interfacial capacitance due to the multi-defect sites in the layered composite.

Highlights

P-PDA molecules were inserted into layered Ni-doped TiO2 nanosheets to prepare p-phenylenediamine/Ni-doped TiO2 (p-PDA/NTO) by following a similar method, as reported in our previous work [9]
The thermogravimetric analysis (TG) curve in Figure 1b shows that the carbon nanosheet in the composite with a lower polymerization temperature has a relatively lower thermal stability, and poly-p-PDA/NTO samples at 200 and 200/300 ◦ C
All show an obvious weight loss below 400 ◦ C in O2 atmosphere, which is due to the incomplete oxidative polymerization and the evaporation of free amino/aromatic rings between metal oxide layers at the lower temperatures

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The development of the next-generation electrode materials for high-power density. LIB is one of the main domains that we urgently need to focus on. Two-dimensional metal oxides are considered to be one kind of potential electrode material for high-performance. LIB due to their short active paths and highly exposed active sites on the surface. The low electronic conductivity seriously restricts their electrochemical properties [1,2,3,4,5]

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Results

Conclusion