Sustainable eco-friendly sub-micron NaCl crystal powder-assisted method to synthesize SiOx/C as anode materials originated from rice husk for lithium-ion batteries
International Conference on Advadced Materials and Devices, Jeju, Korea(2023)
Young Pyo Jeon, Yeon Soo Kim, Tae Han Kim, Sang-hwa Lee, Se Hun Lee, Eun Jung Lee, Hak Ji Lee, Hae Ryeong Cho, Young Joon Yoo, Sang Yoon Park
Abstract
As environmental issues have recently emerged, research in a direction that can minimize environmental hazards in the process of material development as well as material development to solve only the energy density problem of graphite is urgently needed. Another challenge on graphite is that the Paris Agreement committed to reducing greenhouse gas emissions by at least 40% by 2030 compared to 1990 and the governance mainly focused to avoid dangerous climate change by limiting global warming to well below 2°C and pursuing efforts to limit it to 1.5°C. Unfortunately, purifying natural graphite requires a huge amount of hydrofluoric acid in the refinement process to remove containing mineral impurities while manufacturing synthetic graphite intensely demands a lot of electrical energy involved with carbonization and graphitization processes requiring high temperatures of over 3000°C. Isolation of the additive catalyst during the treatment process is also one of the practical problems. Therefore, it is required to develop an alternative solution that can solve multiple problems of a conventional graphite anode, regarding electrochemical performance, environmental pollution, hazardousness of synthesis, and methodological problems of material preparation.
In this study, we introduce SiOx/C produced through the NaCl sub-microm crystal-assisted synthesis method, which can complement environmental destruction, hazards, and complicated preparation processes while improving electrochemical performance using rice husk as a starting material. During the synthesis process, excess added NaCl plays three main roles: catalytic graphitization, activation of carbon, and formation of amorphous silica. In addition, the NaCl used in this process is not completely consumed and can be reused infinitely. As a result, the LIBs using a rice husk-derived SiOx/C through our NaCl sub-micron crystal powder-assisted method exhibited a high initial charge/discharge capacity of 422.05/915.93 mAh∙g-1 at 0.05 A∙g-1 and high cycle stability over 500 cycles. In addition, in the case of electrodes to which the NaCl micro-crystal method was not applied, the specific capacity of 333.96 mAh∙g-1 at a current density of 0.05 A∙g-1 was indicated, whereas the electrode adopting this method showed a high capacity of 479.77 mAh∙g-1 at a current density of 0.05 A∙g-1.