Li4Ti5O12/graphene nanoribbons composite as anodes for lithium ion batteries.

P A Medina,L Le Roux,P Annamalai,H Zheng,B D Fahlman,A Swartbooi,M K Mathe

doi:10.1186/s40064-015-1438-0

P A Medina, L Le Roux + Show 5 more

Open Access

https://doi.org/10.1186/s40064-015-1438-0

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Abstract

In this paper, we report the synthesis of a Li4Ti5O12/Graphene Nanoribbons (LTO/GNRs) composite using a solid-coating method. Electron microscope images of the LTO/GNRs composite have shown that LTO particles were wrapped around graphene nanoribbons. The introduction of GNRs was observed to have significantly improved the rate performance of LTO/GNTs. The specific capacities determined of the obtained composite at rates of 0.2, 0.5, 1, 2, and 5 C are 206.5, 200.9, 188, 178.1 and 142.3 mAh·g−1, respectively. This is significantly higher than those of pure LTO (169.1, 160, 150, 106 and 71.1 mAh·g−1, respectively) especially at high rate (2 and 5 C). The LTO/GNRs also shows better cycling stability at high rates. Enhanced conductivity of LTO/GNRs contributed from the GNR frameworks accelerated the kinetics of lithium intercalation/deintercalation in LIBs that also leads to excellent rate capacity of LTO/GNRs. This is attributed to its lower charge-transfer resistance (Rct = 23.38 Ω) compared with LTO (108.05 Ω), and higher exchange current density (j = 1.1 × 10−3 mA cm−2)—about 20 times than those of the LTO (j = 2.38 × 10−4 mA cm−2).

Highlights

As a most effective and practical technology, lithium ion batteries (LIBs) continue to provide a promising solution to increasing energy demands of portable devices such as mobile phones and laptops
LIBs are explored as promising for electric vehicles (EVs), hybrid electric vehicles (HEVs) and energy storage systems in terms of their high power density, long cycle life and high safety(Armand and Tarascon 2008; Scrosati and Garche 2010)
Graphene nanoribbons (GNRs) strips shown in Fig. 2a had an average width of 75–150 nm

Summary

Introduction

As a most effective and practical technology, lithium ion batteries (LIBs) continue to provide a promising solution to increasing energy demands of portable devices such as mobile phones and laptops. Electrochemical performances The electrochemical behaviour of the LTO/GNRs sample was tested at various charge/discharge rates from 0.2 to 5 C in the potential range of 1–2.5 V vs Li/Li+.

Results

Conclusion