Stabilizing a Si Anode via an Inorganic Oligomer Binder Enabled by Robust Polar Interfacial Interactions
Jianshun Feng, Dong Wang, Qian Zhang, Jie Liu, Yumin Wu, Lei Wang
Abstract
Exploiting macromolecule binders has been demonstrated as an effective approach to stabilize a Si anode with a huge volume change. The macromolecule polymer binders with vast intra/intermolecular interactions lead to an inferior dispersion of binders on a Si active material. Herein, a potassium triphosphate (PTP) inorganic oligomer was exploited as a robust binder to alleviate the problem of capacity fading in Si-based electrodes. PTP has abundant P–O– bonds and P═O bonds, which can form strong ion–dipolar and dipolar–dipolar forces with a hydroxylated Si surface (Si–OH). Particularly, the PTP inorganic oligomer has a short-chain structure and high water solubility, resulting in a superior dispersion of the PTP binder on Si nanoparticles (nano-Si) to effectively enhance the mechanical stability of Si-based electrodes. Hence, the as-prepared Si-based anode exhibits obviously improved electrochemical performance, delivering a charge capacity of 1279.7 mAh g–1 after 300 cycles at 800 mA g–1 with a high capacity retention of 72.7%. Moreover, using the PTP binder, a dense Si anode can be achieved for high volumetric energy density. The success of this study shows that the PTP inorganic oligomer as a binder has great significance for future advanced binder research.