Bio-waste chicken eggshells to store energy

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 47; no. 47; pp. 16828 - 16834
• Main Authors: Minakshi, Manickam, Visbal, Heidy, Mitchell, David R. G, Fichtner, Maximilian
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 04.12.2018
• Subjects: Activated carbon; Animals; Aqueous electrolytes; Calcium carbonate; Calcium Carbonate - chemistry; Capacitance; Carbon - chemistry; Egg Shell - chemistry; Electric Capacitance; Electrochemical analysis; Electrochemical Techniques; Electrodes; Electrolytes; Energy storage; Industrial Waste - prevention & control; Lithium; Lithium - chemistry; Nonaqueous electrolytes; Porosity; Waste Products; X-Ray Diffraction
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c8dt03252a

Bio-waste in the form of chicken eggshells, which contain high amounts of calcium carbonate (CaCO 3 ), is used to store energy. The fine eggshell powders are used as an electrode against a metallic lithium anode in a non-aqueous electrolyte. The initial discharge capacitance of the eggshell system was found to be 232 F g −1 , while the reversible capacitance was 120 F g −1 . Thereon, the cell maintained an excellent capacitance retention of 92% over 1000 cycles. The electrochemical performance obtained is comparable to that of commercially available classical activated carbon (AC) material. CaCO 3 showed a non-faradaic behaviour and the shape of the electrochemical curves resembles that of the AC electrode. The preliminary findings suggest that CaCO 3 from eggshells can be used as the electrode in Li-ion capacitors to store and release charges effectively over a wide electrochemical stability window of 4 V. Using chicken eggshells in this manner not only reduces the amount of bio-waste, but also adds considerable value. A detailed understanding of the electrochemical and physical behaviour of the material is needed in order to improve its performance and to enable its widespread use. Chicken eggshell, a calcite mineral (CaCO 3 ) along with an inner shell membrane, is crushed into a powder to be used as an electrode for a lithium-ion capacitor.