Impact of Surface Chemistry of Silicon Nanoparticles on the Structural and Electrochemical Properties of Si/Ni3.4Sn4 Composite Anode for Li-Ion Batteries

Abstract

Embedding silicon nanoparticles in an intermetallic matrix is a promising strategy to produce remarkable bulk anode materials for lithium-ion (Li-ion) batteries with low potential, high electrochemical capacity and good cycling stability. These composite materials can be synthetized at a large scale using mechanical milling. However, for Si-Ni3Sn4 composites, milling also induces a chemical reaction between the two components leading to the formation of free Sn and NiSi2, which is detrimental to the performance of the electrode. To prevent this reaction, a modification of the surface chemistry of the silicon has been undertaken. Si nanoparticles coated with a surface layer of either carbon or oxide were used instead of pure silicon. The influence of the coating on the composition, (micro)structure and electrochemical properties of Si-Ni3Sn4 composites is studied and compared with that of pure Si. Si coating strongly reduces the reaction between Si and Ni3Sn4 during milling. Moreover, contrary to pure silicon, Si-coated composites have a plate-like morphology in which the surface-modified silicon particles are surrounded by a nanostructured, Ni3Sn4-based matrix leading to smooth potential profiles during electrochemical cycling. The chemical homogeneity of the matrix is more uniform for carbon-coated than for oxygen-coated silicon. As a consequence, different electrochemical behaviors are obtained depending on the surface chemistry, with better lithiation properties for the carbon-covered silicon able to deliver over 500 mAh/g for at least 400 cycles.

Determination of Hansen Parameters of Nanoparticles: A Comparison of Two Methods Using Titania, Carbon Black, and Silicon/Carbon Composite Materials

“…Since the Si/C nanoparticles have a carbon-rich surface, it makes them less effective for forming hydrogen bonds. [25,31,32] This is reflected by the hydrogen interaction parameter that is low, independent if IEA or PSDC was used.…”

Nanostructured Materials for Energy Storage and Conversion

“…The ten articles published in this Special Issue showcase the different applications of nanomaterials in the field of energy storage and conversion, including electrodes for Li-ion batteries (LIBs) and beyond [1][2][3], photovoltaic materials [4][5][6], pyroelectric energy harvesting [7], and (photo)catalytic processes [8][9][10]. The scientific contributions are briefly summarized in the following.…”

“…The improved structural integrity and stability allows for a high specific capacity of 524/313 mAh/g to be maintained after 1100/6500 cycles. In the work of Azib et al, the surface chemistry of Si nanoparticles in a Si/Ni 3.4 Sn 4 composite anode is modified by a coating of either carbon or oxide [2]. The coating strongly reduces the reaction between Si and Ni 3.4 Sn 4 during the composite's preparation by ball milling.…”