Integrating robust SEI on recycled micro-sized silicon scrap for stable lithium ion battery
Haoyu Ma, Baogang Zhao, Zhuobin Han, Mengjia Yu, Kexin Liu, Zhongting Wang, Bingqing Yan, Yinghao Zhou, Xinliang Feng, Rongrong Jia, Yin Zhao, Zhuyi Wang, Yumei Wang, Li Lü, Shuai Yuan, Liyi Shi, Yingying Lv
Abstract
Silicon (Si) based anode materials for lithium ion (Li + ) batteries have garnered significant attention due to their high specific capacity, low lithium insertion potential, but higher cost than usual graphite anode. The slicing of photovoltaic silicon generate a significant amount of silicon scrap, resulting in substantial waste and pollution. Here, we present a novel technique that an organic molecular encapsulation with elastic polymer silane coupling agent (KH570) crosslinking with trifluoromethyl ethyl methacrylate (TFEMA) on the surface of micrometer-scale photovoltaic Si scrap particles via hydrolysis followed by polymerization. The fluorination-terminated functional groups would induce a more stable LiF-rich solid electrolyte interface (SEI). resulting in reduced SEI and charge transfer resistance. More importantly, the crosslinking network of the elastic polymer, enables a high capacity of 985 mAh g −1 (5 times than pure Si scrap) over 500 cycles at 5 A g −1 and achieves a 90 % retention rate after 100 cycles (131 mAh g −1 ) in a full cell system. Furthermore, the modified Si could be matching with a polymer-based solid-state electrolyte, delivering a specific capacity of 1000 mAh g −1 . This organic molecular encapsulation technique is straightforward, highly reproducible and demonstrate considerable practical value for the recycling of resources.