Sodium Alginate: A Water-Processable Binder in High-Voltage Cathode Formulations

Francesca Bigoni,Catia Arbizzani,Francesca De Giorgio,Francesca Soavi

doi:10.1149/2.0281701jes

Francesca Bigoni, Catia Arbizzani + Show 2 more

Open Access

https://doi.org/10.1149/2.0281701jes

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Abstract

Binders are electrochemically inactive electrode components. However, their chemical and physical nature greatly affects battery performance and plays a key role in electrode integrity and interface reactivity. The binders thus have a strong impact on battery capacity retention and cycle life. Water-processable binders would make the electrode preparation process cheap and environmentally friendly and provide a viable alternative to polyvinylidene difluoride (PVdF). Here we report the use of sodium alginate (SA) as binder for LiNi0.5Mn1.5O4 (LNMO), one of the most promising cathode materials for high-voltage and high-energy LIBs. We demonstrate that electrodes with high mass loading containing SA have excellent specific discharge capacity (120 mAh g−1 at C/3 and 100 mAh g−1 at 5C) with negligible overpotentials in conventional electrolyte based on ethylene carbonate (EC): dimethyl carbonate (DMC) and 1 M LiPF6, where the reactivity of LNMO is known to negatively affect stability. The electrodes with SA also show a good stability over subsequent cycles of charge and discharge at 1C with capacity retention of 95% and 86% with respect to the initial cycles at the 100th and 200th cycle.

Highlights

FOCUS ISSUE OF SELECTED PAPERS FROM IMLB 2016 WITH INVITED PAPERS CELEBRATING 25 YEARS OF LITHIUM ION BATTERIES
We report that the use of Sodium alginate (SA) binder with high LNMO loading enhances the cycling performance of the electrodes with respect to the use of polyvinylidene difluoride (PVdF) and offers the advantage of enabling water-process methods for the preparation of high-voltage, high-loading electrodes, a key feature in view of large-size battery production for electric vehicles
Galvanostatic charge/discharge cycles between 3.5 and 4.8 V vs. Li+/Li were carried out to evaluate the discharge performance of the cathode materials prepared with the two binders at different current densities and their cycling stability when subjected to repeated charge and discharge cycles

Summary

Introduction

FOCUS ISSUE OF SELECTED PAPERS FROM IMLB 2016 WITH INVITED PAPERS CELEBRATING 25 YEARS OF LITHIUM ION BATTERIES. LNMO is one of the most promising cathode materials for LIB use in electric vehicles thanks to its good theoretical capacity (146.7 mAh g−1), high operating voltage (4.7 V vs Li+/Li) and good high-rate performance.[36,37] its reactivity with conventional electrolytes based on ethylene carbonate (EC): dimethyl carbonate (DMC) and 1 M LiPF6 is well known.[38] We report that the use of SA binder with high LNMO loading enhances the cycling performance of the electrodes with respect to the use of PVdF and offers the advantage of enabling water-process methods for the preparation of high-voltage, high-loading electrodes, a key feature in view of large-size battery production for electric vehicles.

Results

Conclusion