Preplanting Nanosilica into Binderless Battery Electrodes for High-Performance Li-Ion Batteries

Abstract

The energy density of Li-ion batteries (LIBs) can be effectively enhanced by increasing the thickness of a LiNi x Mn y Co1–x–y O2 (NMC) electrode and limiting the use of inactive components. However, the deficiency of a binder in thick NMC cathodes causes mechanical failure, such as crack formation and delamination, resulting in performance deterioration. To address the detrimental issues associated with thick electrodes, this study proposes the preplanting of nanosilica (SiO2) into a NMC composite electrode. SiO2 preplanted in the PVDF polymer solution can alter the viscoelastic properties of the NMC slurry and regulate the binder distribution within the NMC cathode. A lower binder concentration at the interface assisted by SiO2 preplanting enhances the charge transfer without compromising adhesion. The hydrophilic nature of fumed SiO2 can facilitate the penetration of the electrolyte through a thick NMC cathode, enhancing its high-power capability up to 4 C-rate. Owing to the HF scavenging role of fumed SiO2, the SiO2 preplanted cathode exhibited stable cycling at an elevated temperature (60 °C) by alleviating the side reactions triggered by salt decomposition.