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Aug 19, 2016 - Fax: +86 10 68451429., *E-mail: [email protected]. .... interest for the next-generation lithium-ion batteries, their long-term cyclabi...
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Surface Modification of Li-rich Cathode Materials for Lithium-ion Batteries with PEDOT:PSS Conducting Polymer Feng Wu, Jianrui Liu, Li Li, Xiaoxiao Zhang, Rui Luo, Yusheng Ye, and Renjie Chen ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.6b07431 • Publication Date (Web): 19 Aug 2016 Downloaded from http://pubs.acs.org on August 20, 2016

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ACS Applied Materials & Interfaces

Surface Modification of Li-rich Cathode Materials for Lithium-ion Batteries with PEDOT:PSS Conducting Polymer Feng Wua,b, Jianrui Liua, Li Lia,b*, Xiaoxiao Zhanga, Rui Luoa, Yusheng Yea, Renjie Chena,b* a. School of Materials Science & Engineering, Beijing Key Laboratory of Environmental Science and Engineering, Beijing Institute of Technology, Beijing 100081, China b. Collaborative Innovation Center of Electric Vehicles in Beijing, Beijing 100081, China Corresponding author:

[email protected] (L. Li); [email protected] (R.Chen)

Tel: +86 10 68912508; Fax: +86 10 68451429 ABSTRACT Composites

of

lithium-rich

Li1.2Ni0.2Mn0.6O2

and

poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) are synthesized through co-precipitation followed by a wet coating method. In the resulting samples, the amorphous conductive polymer films on the surface of the Li1.2Ni0.2Mn0.6O2 particles are 5–20 nm thick. The electrochemical properties of Li1.2Ni0.2Mn0.6O2 are obviously enhanced after PEDOT:PSS coating. The composite sample with an optimal 3 wt% coating amount exhibits better rate capability and cycling properties than those of Li1.2Ni0.2Mn0.6O2, with an excellent initial discharge capacity of 286.5 mA h g−1 at a current density of 0.1 C and discharge capacity remained 146.9 mA h g−1 at 1 C after 100 cycles. The increased performances are ascribed to the high conductivity of the PEDOT:PSS coating layer, which can improve the conductivity of composite material. The PEDOT:PSS layer also suppresses the formation and growth of a solid electrolyte interface. Surface modification with PEDOT:PSS is a feasible approach to improve the comprehensive properties of cathode materials.

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KEYWORDS: Lithium-ion battery, Cathode material, Surface modification, PEDOT:PSS, Electrochemical properties.

1. INTRODUCTION With the development of electric vehicles, smart phones, and laptops, the demand for lithium ion batteries (LIBs) has increased.1-2 However, the traditional cathode materials such as LiCoO2, LiFePO4, and LiMn2O4 with limited specific capacity (