Micrometer‐Sized SiMg_yO_x with Stable Internal Structure Evolution for High‐Performance Li‐Ion Battery Anodes

Abstract

In recent years, micrometer‐sized Si‐based anode materials have attracted intensive attention in the pursuit of energy‐storage systems with high energy and low cost. However, the significant volume variation during repeated electrochemical (de)alloying processes will seriously damage the bulk structure of SiOx microparticles, resulting in rapid performance fade. This work proposes to address the challenge by preparing in situ magnesium‐doped SiOx (SiMgyOx) microparticles with stable structural evolution against Li uptake/release. The homogeneous distribution of magnesium silicate in SiMgyOx contributes to building a bonding network inside the particle so that it raises the modulus of lithiated state and restrains the internal cracks due to electrochemical agglomeration of nano‐Si. The prepared micrometer‐sized SiMgyOx anode shows high reversible capacities, stable cycling performance, and low electrode expansion at high areal mass loading. A 21700 cylindrical‐type cell based on the SiMgyOx‐graphite anode and LiNi0.8Co0.15Al0.05O2 cathode demonstrates a 1000‐cycle operation life using industry‐recognized electrochemical test procedures, which meets the practical storage requirements for consumer electronics and electric vehicles. This work provides insights on the reasonable structural design of micrometer‐sized alloying anode materials toward realization of high‐performance Li‐ion batteries.

Assembly: A Key Enabler for the Construction of Superior Silicon‐Based Anodes

“…Hence, novel silicon-based electrode materials with high energy density have become a major focus of research and innovation, except for the optimization of the cell structure. [17][18][19][20] To effectively achieve the goal of high energy density for composite electrodes, a strategy has been proposed for assembling silicon-based nanomaterials into micron-sized hierarchical structures. [21][22][23][24] Assembly is a behavior in which basic structural units (molecules, nano materials, micron materials, etc) form a stable hierarchical architecture with regular geometric appearance based on the interaction of non-covalent bonds.…”

“…Hence, novel silicon‐based electrode materials with high energy density have become a major focus of research and innovation, except for the optimization of the cell structure. [ 17 , 18 , 19 , 20 ]…”

Advances of Synthesis Methods for Porous Silicon-Based Anode Materials

“…To address the issues associated with Si, especially volume expansion, massive efforts have been made, including: avoiding materials pulverization via the design of silicon nanostructures, ( An et al, 2020 ; Qi et al, 2020 ; Sun et al, 2022a ; Sun et al, 2022b ; Li et al, 2022 ) improving cycling stability through SiO/SiO x -based anode materials, ( Wang et al, 2020a ; Tian et al, 2022 ) and increasing electronic/ionic conductivities through utilizing advanced electrolyte additives and novel binders. ( Huang et al, 2019 ; Zhao et al, 2021 ; Zhou et al, 2021 ; Zhu et al, 2021 ) The 3D porous Si-based materials have enough internal voids to accommodate volume expansion due to the existence of their large pores, so that their structures can maintain their integrity during the processes of lithiation/delithiation, avoiding pulverization of silicon-based materials.…”

A highly stable pre-lithiated SiOx anode coated with a “salt-in-polymer” layer

“…Recently, the micro-sized Si suboxide (MSiO x , x E 1) has received much more attention due to its high tap density, low cost and relatively better cycling stability than pure Si anodes. [1][2][3][4] During the initial lithiation process, inactive components, such as Li oxide (Li 2 O) and Li silicates (Li x SiO y ), could be generated within MSiO x , which will function as a buffering matrix for the active Si nanodomains and therefore enabled an alleviated volume change and improved the cycling stability of MSiO x anodes compared with pure Si anodes. 5,6 However, one problem is that the formation of inactive Li compounds will lead to a low ICE (o75%) of MSiO x anodes.…”

“…To restrain the volume expansion and improve the cycling stability of Si-based anodes, strategies like elemental doping, 4,11 electrolyte design, [12][13][14][15] binder design, [16][17][18][19] and interface design 20,21 have been employed. Among the various strategies, we noticed that the composite interface or the SEI design is highly efficient in reducing the volume expansion and improving the electrochemical performance of Si-based anodes.…”