Sodium-Alginate-Based Binders for Lithium-Rich Cathode Materials in Lithium-Ion Batteries to Suppress Voltage and Capacity Fading

A series of sodium alginate (SA)-based binders are prepared for Li-rich and Mn-based oxides (LRMO) to address capacity loss and voltage fading issue. Our results demonstrate that the Ba2+ and Al3+ cations crosslinked SA binders can significantly enhance the electrochemical performance. A small voltage fading of 0.326V and a capacity retention of 82.5% are displayed with Ba2+-doped SA binder; and a voltage decay of 0.208 V and a capacity retention of 99.9% are measured on the Al3+ -doped one. FESEM and TEM observations prove that the doped SA based binders can form a coating layer on the surface of the primary particles, which functions as an effective screen to prevent the active materials from being etched by the electrolyte and hence stabilizes the layered crystal structure of the LRMO. XPS depth profiles of the cycled LRMO with SA-based binders further confirm that the Mn element dissolution, an issue which causes severe capacity loss and irreversible structural transformation, can be effectively alleviated by Ba2+- and Al3+-doped SA binders. On this basis, the usage of SA-based binders are a promising approach to suppress the voltage and capacity fading of LRMO.