Issue 12, 2017

Intrinsic conductivity optimization of bi-metallic nickel cobalt selenides toward superior-rate Na-ion storage

Abstract

Enhancing the conductivity of electrode materials is critically important for improving the high-rate performance of Na-ion batteries (NIBs). Herein, we report a multifaceted strategy for optimizing the conductivity and electrochemical properties of nickel cobalt selenides via the combination of fine component regulation and C coating. The electrical conductivity of C@Ni0.33Co0.67Se2/C nanofiber (CNF) (Co0.67) hybrids achieved in this study was 0.3733 S mm−1, a conductivity five-fold higher than that of selenides with a Ni/Co ratio of 2 : 1. Coupled with desirable three-dimensional (3D) nanobrush morphology and the 1D conducting path of CNFs, the Co0.67 electrode achieved a superior rate performance of 413.1 mA h g−1, even at 2 A g−1. Furthermore, the Co0.67 electrode exhibited an impressive cycling performance of 499 mA h g−1 after 100 cycles (exhibiting an 89.5% capacity retention of the second cycle). Finally, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry analysis at different sweep rates were conducted to demonstrate the Co0.67 electrode's fast charge/ion transport ability and increased electrode kinetics.

Graphical abstract: Intrinsic conductivity optimization of bi-metallic nickel cobalt selenides toward superior-rate Na-ion storage

Supplementary files

Article information

Article type
Research Article
Submitted
12 Sept. 2017
Accepted
18 Okt. 2017
First published
19 Okt. 2017

Mater. Chem. Front., 2017,1, 2656-2663

Intrinsic conductivity optimization of bi-metallic nickel cobalt selenides toward superior-rate Na-ion storage

C. Wu, Y. Wei, Q. Lian, C. Cui, W. Wei, L. Chen and C. Li, Mater. Chem. Front., 2017, 1, 2656 DOI: 10.1039/C7QM00419B

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