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

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. (C) The Author(s) 2016. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. All rights reserved.