Improving the Performance of SiO_x/Carbon Materials for High Energy Density Commercial Lithium‐Ion Batteries Based on Montmorillonite

Abstract

Silicon is recognized as the most promising anode material for the next-generation battery. In order to improve the processing and electrochemical performances, a silicon-based anode composite was synthesized using silicon, montmorillonite and carboxymethylcellulose (CMC) as raw materials. The processing parameters, such as particle size and specific surface area, were ameliorated to be consistent with those of commercial lithium-ion battery (LIB) anode materials. As an anode composite, it perfectly matched with high nickel ternary cathode materials and showed excellent electrochemical properties. The discharge capacities were all above 1000 mAh/g and the coulombic efficiency of each step was over 99 % throughout the 50 cycles at 1 C (1100 mA/g). Its superior performances are attributed to the unique layered structure, which buffers the volume expansion and enhances the stability of the solid electrolyte interface (SEI) film on the anodic electrode, suggesting a perspective future in designing high energy density commercial LIBs.

Montmorillonite-based materials for electrochemical energy storage

“…Fortunately, this problem can be efficiently settled by compounding MMT with highly conductive materials such as conductive carbon, graphene, conductive metallic compounds, and so on. 6,18,21,146,147 In addition to improving the electronic conductivity of MMT, researchers also work towards improving the ion transport properties of MMT-based composite electrodes for secondary batteries via intercalation treatments. 21,146 Recently, many papers reported MMT-based composite electrodes with outstanding electrochemical performance both in metal-ion batteries and LSBs.…”

“…L. Feng et al designed a facile method for synthesizing a silicon-based LIB anode based on MMT. 147 The main active component of the composite anode was SiO x /C. Carboxymethylcellulose (CMC), as the carbon source, could be turned into a multipoint contacting porous structure, which stabilized the microstructure and improved the electronic conductivity of the composite anodes.…”

Effects of B and P Doping on Electronic Structure and Lithium Diffusion Properties of Si(100) Surface

“…The work function is defined as the minimum energy required to move an electron from the interior of a solid to surface. On the basis of structural relaxation, the work function of the Si(100) surface was calculated using Equation (4) [17] 𝜙 = E vac − E F (4) where𝜑is the work function, E vac is the electrostatic potential energy in vacuum, and E F is the Fermi energy.…”

“…[1] Currently, anode material used for commercial lithium-ion batteries is graphite, its capacity is 372 mAh g −1 , which is insufficient for fabricating lithium-ion batteries with high specific capacity and high energy density. [2][3][4] Besides, the diffusion rate of lithium in graphite is low, which reduces the electrode's rate performance. [5] Compared with graphite, silicon has a high theoretical capacity (3590 mAh g −1 [6] ), especially when Li 22 Si 5 is formed, its theoretical capacity can reach 4200 mAh g −1 .…”