Title: Understanding the role of water-soluble guar gum binder in reducing capacity fading and voltage decay of Li-rich cathode for Li-ion batteries

Abstract

The practical application of high-capacity Li-rich cathode materials is hindered by capacity fading and voltage decay. The capacity fading and voltage decay could be effectively overcome by using water-soluble guar gum (GG) binder instead of traditional polyvinylidene fluoride (PVDF). However, the specific role of the GG binder is not clear yet, though the GG binder can significantly improve the electrochemical performance of Li-rich cathode. To understand the effect of GG binder on the morphology, microstructure of electrode and electrode/electrolyte interfaces, ex-situ scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray adsorption near edge spectroscopy (XANES), in-situ electrochemical impedance spectroscopy (EIS) were applied to comparatively study the charge-discharge processes of Li-rich Li_1.2Ni_0.2Mn_0.6O₂ cathode when using GG and PVDF as binders. The results indicate that the GG binder can prevent electrode crack and active material loss, ascribing to the strong mechanical adhesion of GG binder with active material particles and current collector. It has found that the GG binder can also induce the formation of a uniform layer on Li_1.2Ni_0.2Mn_0.6O₂ particles’ surface. As a consequence, both the electrolyte decomposition and the electrode corrosion were significantly inhibited. The strong chelation between Mn²⁺ and polar OH group restrain Mn ion dissolution, which contributes tomore » surface structural transformation mitigation. Here, our study reveals the role of water-soluble GG binder in reducing capacity fading and voltage decay of Li-rich material and is of great importance in design functional binders for high-performance Li-rich electrodes.« less

Authors:

Yin, Zu-Wei ^[1]; Zhang, Tao ^[2]; Zhang, Shao-Jian ^[2]; Deng, Ya-Ping ^[2]; Peng, Xin-Xing ^[1]; Wang, Jian-Qiang ^[3]; Li, Jun-Tao ^[2]; Huang, Ling ^[2]; Zheng, Haimei ^[4]; Sun, Shi-Gang ^[2]

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+ Show Author Affiliations

1. Xiamen Univ. (China); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
2. Xiamen Univ. (China)
3. Chinese Academy of Sciences (CAS), Shanghai (China)
4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)

Publication Date:

Wed May 06 00:00:00 EDT 2020

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division; National Natural Science Foundation of China (NSFC); China Scholarship Council; USDOE

OSTI Identifier:

1642700

Alternate Identifier(s):

OSTI ID: 1775727

Grant/Contract Number:  

AC02-05CH11231; 21621091; 201606310151

Resource Type:

Accepted Manuscript

Journal Name:

Electrochimica Acta

Additional Journal Information:

Journal Volume: 351; Journal ID: ISSN 0013-4686

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

25 ENERGY STORAGE; lithium ion batteries; Li-rich material cathode; water-soluble binder; in-situ and ex-situ techniques; capacity fading; voltage decay