Development of Modified Silicon Nanoparticles for Energy Storage

Abstract

Due to the outstanding electrochemical properties, lithium-ion batteries have become a widely used energy storage technology for diverse types of devices. However, rapid progress in portable electronic devices and electric vehicles requires further essential improvement in the power and energy densities of lithium-ion batteries (LIBs) [1]. Conventional LIBs technology has reached the limit of its gravimetric / volumetric energy densities and power capabilities, reducing its ability to power new electronic devices and / or work as large batteries [2].Among the promising candidates for anode materials, silicon (Si) has several advantages, including high theoretical capacity (3579 mAh g-1 for Li15Si4 at room temperature), low reaction potential against cathode material, environmental compatibility, low toxicity, and low cost. However, for the practical implementation of Si anodes in LIBs, it is necessary to consider one big critical issue: adaptation of large volume changes. Significant change in volume (4300%) during lithiation / delitration, leads to the volume expansion and grinding of Si particles, which leads to a rapid loss of electrode capacity, as shown in Figure 1aThis work presents the development of a new technology for the preparation of a composite anode material based on spinel Li4Ti5O12 (LTO) and Si with the addition of polyacrylonitrile (PAN) by liquid-phase coating, which demonstrates a synergistic positive effect on the performance of Si anodes (Fig. 1b). The idea lies in the coating the surface of silicon particles with LTO and PAN to suppress the volume expansion and improve the conductivity. The unique structure of LTO with zero deformation during lithiation / delitiation will help to withstand the volume change whereas PAN coating will improve the conductivity of the whole system.AcknowledgementsThis work was supported by the research grant AP05133706 “Innovative high-capacity anodes based on lithium titanate for a next generation of batteries” from the Ministry of Education and Science of the Republic of Kazakhstan and Collaborative Research Program for 2020-2022 "Three-Dimensional All Solid State Rechargeable Batteries".