Core Shell Structured Silica/Porous Carbon Composite as an Efficient Anode for Lithium Ion Batteries

Abstract

Si‐based materials are taken into consideration as suitable anode materials for lithium‐ion (Li‐ion) batteries due to their high specific capacity. However, their cycle life is limited due to high volumetric changes during discharging and charging in Li‐ion battery (LIB). Silica (SiO2) is abundantly present in nature, but standalone delivers moderate Li storage capacity. Commercially, graphite is considered as efficient anode in LIB. The current research focuses on improving the performance of silica as anode material to achieve the best specific capacity of LIBs. Herein, the core‐shell‐structured silica/porous carbon composite (50:50, wt%) is synthesized using a hydrothermal method. The shell of porous carbon not only covers the core silica but also provides a very high surface area of ≈1057 m2 g−1 to the composite. The synthesized silica/porous carbon composite acts as an active anode material in Li‐ion half‐cell, which shows the best specific capacity of ≈642 mAh g−1 at 700 cycles at 100 mA g−1 current density and a high capacity retention of ≈97%. The porous carbon on silica helps in the uniform percolation of the electrolyte. It also provides a conducting path to the electrons and further reduces Li‐ion diffusion time by producing more active sites. The shell of porous carbon on core‐silica helps to suppress the volumetric changes that happen during the lithiation and de‐lithiation process. Due to these advantages, the core‐shell‐structured silica/porous carbon composite anode shows consistent and stable cycling performance over large number of cycles.

Post-mortem study and long cycling stability of silica/carbon composite as anode in Li-ion cells

“…The anode can deliver and accept charge at higher rates due to improved conductivity of carbon and structural stability, which makes it appropriate for applications requiring quick charging and discharging. The specific capacity of anode is increased when silica is added to the carbon matrix [28,29]. This may enhance cost-effectiveness of LIBs and increase their ability to compete in the energy storage industry.…”