	US 12,444,738 B2
	Methods of adjusting carbon and silica content in rice hull ash (RHA) byproducts to control carbothermal reduction forming nanostructured silicon carbide, silicon nitride, silicon oxynitride nanocomposites
Mengjie Yu, Ann Arbor, MI (US); Richard Laine, Ann Arbor, MI (US); and Eleni Temeche, Ann Arbor, MI (US)
Assigned to The Regents of The University of Michigan, Ann Arbor, MI (US)
Appl. No. 18/689,910
Filed by THE REGENTS OF THE UNIVERSITY OF MICHIGAN, Ann Arbor, MI (US)
PCT Filed Sep. 8, 2022, PCT No. PCT/US2022/042886 § 371(c)(1), (2) Date Mar. 7, 2024, PCT Pub. No. WO2023/039049, PCT Pub. Date Mar. 16, 2023.
Claims priority of provisional application 63/241,820, filed on Sep. 8, 2021.
Prior Publication US 2025/0132323 A1, Apr. 24, 2025
Int. Cl. H01B 1/04 (2006.01); C01B 32/97 (2017.01); H01M 4/485 (2010.01)

CPC H01M 4/485 (2013.01) [C01B 32/97 (2017.08); H01B 1/04 (2013.01)]

12 Claims

1. A method of making a silicon carbide or silicon nitride from rice hull ash (RHA) byproduct, the method comprising:

removing silicon oxide from a rice hull ash (RHA) byproduct to form a silica depleted rice hull ash (SDRHA) by reacting the rice hull ash (RHA) with a hindered diol in the presence of a catalytic base;

heating the silica depleted rice hull ash product (SDRHA) comprising silicon oxide at less than or equal to about 65% by weight and carbon at greater than or equal to about 35% by weight in an environment free of any additional carbon sources, comprising an inert atmosphere, and having a temperature of greater than or equal to about 1,200°C to less than or equal to about 1,700°C for a carbothermal reaction that forms a product comprising at least one of silicon carbide (SiC), silicon nitride (Si₃N₄), and silicon oxynitride (Si₂N₂O).