A Li4Ti5O12(LTO)/N-doped reduced graphene oxide (RGO) composite is proposed using dual functional nitrogen doping source to prevent RGO restacking and achieve uniform nitrogen doping on RGO sheets to increase the rate performance of high-rate lithium ion batteries. The pore structure (both meso- and macro pores) is developed when RGO restacking is prevented, facilitating electrolyte ion diffusion to active sites with lower resistance. Uniform nitrogen doping on RGO sheets with high nitrogen contents provides additional free electrons to the sheets, resulting in increased electronic conductivity. Cyanamide is used as the nitrogen doping source for the N-doped RGO as well as a nanospacer between the RGO sheets. In the composite, the nitrogen content of the RGO sheets is 2.3 wt%, which increases the electronic conductivity of the composite to 1.60 S cm−1. The specific surface area of the composite is increased to 35.8 m2 g−1. Thus, the composite structure with the N-doped RGO sheets and porous secondary particles has high electrical conductivity and high ion accessibility. The LTO/N-doped RGO composite demonstrates excellent electrochemical performance with a low resistance of 48.4 Ω, a high specific capacity of 117.8 mAh g−1 at 30 C, and good cycle stability.
Bibliographical noteFunding Information:
This research was supported by a grant from the Technology Development Program for Strategic Core Materials funded by the Ministry of Trade, Industry & Energy, Republic of Korea (Project No. 10047758 ). This research was also supported by the Materials and Components Technology Development Program of MOTIE/KEIT, Republic of Korea [ 10062226 , Development of high-capacitance (0.2F/cm 2 ) Edge-exposed graphene electrode and high-voltage (3.5V) polymer electrolyte for flexible supercapacitor]. This research was also supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Science, ICT& Future Planning ( 2015R1A2A2A03006633 ).
© 2016 Elsevier B.V.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Energy Engineering and Power Technology
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering