Ga-Doped LLZO Solid-State Electrolyte with Unique "Plate-like" Morphology Derived from Water Hyacinth (Eichhornia crassipes) Aquatic Weed: Waste to Wealth Conversion.

Abstract

An attempt has been made for the first time to convert waste biomass such as water hyacinth (WH) to a functional energy material in a cost-effective way. The present research describes a novel exo-templating methodology to develop engineered microstructure of Ga-doped Li7La3Zr2O12 (Li6.25La3Ga0.25Zr2O12, referred as WH-Ga-LLZO) solid-state electrolyte for its use in all solid-state lithium batteries (ASSLBs) by mimicking the intercellular structure of water hyacinth (Eichhornia crassipes), an invasive and noxious aquatic plant. The developed exo-templated methodology offers a low calcination temperature of 1000 °C in air where all the major peaks could be indexed as cubic garnet, as confirmed by XRD. The FESEM micrographs revealed a unique “plate-like” morphology that mimicked the intercellular structure of water hyacinth fiber. The bulk lithium-ion conductivity in the WH-Ga-LLZO electrolyte was found to be 3.94 × 10–5 S/cm. Li/WH-Ga-LLZO/Li cells were galvanostatically cycled for a continuous 295 h with increasing step current densities from 28 μA/cm2 without a short circuit. The highest current density as measured for maximum polarization in a symmetric cell was found to be 452 μA/cm2. The WH exo-templated methodology was thus developed and optimized and can be extended for synthesizing any application-specific multifunctional materials.