Interface Heteroatom‐doping: Emerging Solutions to Silicon‐based Anodes

Abstract

Silicon-based composites have been recognized as a promising anode material for high-energy lithium-ion batteries (LIBs). However, the intrinsically low conductivity and the huge volume expansion during lithiation/delithiation progresses impede its further practical applications. In the past decades, numerous efforts have been made for surface and interface modification of Si-based anodes. Among these, doping of active materials with heteroatoms is one promising method to endow silicon many unmatched electrochemical properties. In this review, we focus on the effects of heteroatom doping on the interfacial properties of Si-based anodes, and some typical strategies for the interface doping are highlighted. We aim to give some reference for interfacial doping of Si-based anodes in LIBs. 2 3 4 5 6 7 8

Lithium/Boron Co-doped Micrometer SiOx as Promising Anode Materials for High-Energy-Density Li-Ion Batteries

“…The above results indicated that greatly suppressed cracking and pulverization could be achieved for the Li/B-SiO x @C anodes, which is extremely important for its significantly improved cycling and rate performance. Heteroatom doping can reform the internal chemical bonding and structure of Si-based anodes, which is therefore in favor of maintaining the structural integrity and improving the electrochemical performance of Si-based anodes. − It is believed that the B doping plays a key role in the formation of a strong bonding network within the Li/B-SiO x @C particles and therefore endows the Li/B-SiO x @C anodes with great resistance to cracking and pulverization during cycling and significantly improves the cycling and rate performance. ,, In Figure d,h, the Young’s modulus of lithiated SiO x @C and Li/B-SiO x @C anodes was obtained via AFM characterization. The Li/B-SiO x @C anode exhibited a greatly higher Young’s modulus (3283.82 MPa) than the SiO x @C anode (425.22 MPa), implying the strong bonding networks within the lithiated Li/B-SiO x @C anode …”

“…Heteroatom (e.g., phosphorus (P), boron (B), aluminum (Al), and magnesium (Mg)) doping can reform the electronic structure, chemical bonding, and interfacial property of Si-based anodes, thereby alleviating or reducing the volume expansion of Si-based anodes and improving their electrochemical performance. − For example, Zou et al reported a coral-like P-doped Si anode showing an excellent rate capability (911 mA h g –1 at 16 A g –1 ) and long cycling stability (1564 mA h g –1 after 100 cycles at 2 A g –1 ). Sun et al employed B doping and carbon nanotubes to enable the stable cycling of Si anodes with a capacity retention of 88.2% after 200 cycles.…”

Structure Design and Performance of the Graphite/Silicon/Carbon Nanotubes/Carbon (GSCC) Composite as the Anode of a Li-Ion Battery

“…A semicircle is shown in the high-frequency region, which corresponds to the charge-transfer impedance (R ct ). 49,50 The sloping straight line at the low frequency region is related to Warburg impedance, 51 indicating the resistance of ion diffusion into the active material. 52 It can be obtained that the R ct of the GSCC electrode is about 72 Ω, which is lower than those of the SC (291 Ω) and GSC (138 Ω) electrodes, indicating that the introduction of Gr and the amorphous carbon layer can significantly improve the electronic conductivity of the materials.…”

Organic/Inorganic Hybrid Fibers: Controllable Architectures for Electrochemical Energy Applications

“…Among alloying‐type materials, Si has received distinctive attention because of its high theoretical capacity up to 4200 mA h g −1 and natural abundance. [ 106 ] Early in 2012, Gu and co‐workers probed the lithiation behavior of silicon nanoparticles attached to (embedded in) a CNF using in situ TEM and theoretical analysis. [ 107 ] As shown in Figure 11d , e , compared to the attached structure, the lithiated silicon nanoparticles embedded in a carbon matrix will result in a high stress field, which may lead to the fracture of the CNF.…”