Silicon Anodes for High‐Performance Storage Devices: Structural Design, Material Compounding, Advances in Electrolytes and Binders

Abstract

Silicon has an extremely high theoretical capacity, a low voltage platform, and abundant natural reserves. It is considered to be one of the most promising anode materials for lithium-ion batteries. However, there are still many problems with silicon as an anode material for lithium-ion batteries. During the lithiation/delithiation of silicon, a huge volume expansion occurs, causing the silicon particles to pulverize and the capacity to drop sharply. Furthermore, the continuous increase in the silicon surface solid electrolyte interphase (SEI) films and the poor conductivity of silicon affect the specific capacity of the battery. Means to improve silicon-based anodes with regard to electrode cycling performance and electrode capacity include structural design, composite preparation, or improvements in electrolytes and binders (for example, designing silicon nanomaterials of different dimensions from 0D to 3D, including silicon nanoparticles, nanowires, nanorods, thin films, porous silicon, and core-shell structures). Silicon has been combined with different materials to buffer its own volume expansion, resulting in excellent performance. In addition, the design of a reasonable electrolyte solution, as well as the development of a selfhealing binder is one of the main methods to improve Sibased anodes. In recent years, sodium/potassium ion batteries have been increasingly studied, and silicon and sodium/potassium can be alloyed. The corresponding theoretical capacity can reach 954 mAh g À 1 and 955 mAh g À 1 , respectively. Advances in silicon-based anodes for sodium/ potassium ion storage are summarized herein.ductility. [25] It can increase the conductivity of silicon and adapt to the large volume expansion of silicon. In addition, some are compounded with silicon or metal or metal oxides. Such as copper, silver, tin oxide and titanium oxide. [39][40][41][42][43][44] In addition to changing the silicon's own morphological structure and preparing composite materials, the design and selection of electrolytes and binders is to improve the performance of silicon-based electrodes from the outside. By selecting the appropriate electrolytes, the electrode materials can be effectively reduced deterioration. At present, various additive-modified organic solvent electrolytes, ionic liquid electrolytes, and all-solid electrolytes are widely used in silicon-based anodes. [45][46][47][48] In addition, it is widely applicable to the binder polyvinylidene fluoride(PVDF) of lithium ion battery electrode materials, but

Challenges and Recent Progress on Silicon‐Based Anode Materials for Next‐Generation Lithium‐Ion Batteries

“…After the full lithiation, the silicon nanowire obtained large expansion (≈280%). [ 12 ] This expansion could generate significant mechanical stress on the surface of Si particles, leading to the swelling of electrode and pulverization of Si particles [2a,13] . The electrode swelling could cause the electrode materials to crack and peel off, which causes the loss of electrical contact between Si particles as well as Si particles and current collector, resulting in formation of nonactive Si and low electrical conductivity.…”

“…In addition, the intrinsic low electronic conductivity and Li‐ion diffusion of Si limit the development of full capacity and rate capability of Si anode. [ 1–4,7,11,13,15,16 ]…”

“…Electrolyte plays significant role in passivating the Si/electrolyte during the initial lithiation process and transport ions to connect the silicon‐based anode with Li ion, isolate electrons and determine the electrochemical window [13b,15b,67] . Electrolyte components of salts, [ 68 ] solvents, [9b,69] and additives [ 70 ] have profound influence on the solvation structure, interfacial stability, electrode dissolution, cost, safety, and overall electrochemical performance.…”

Self-Healing Systems on Anodes for Next Generation Energy Storage Devices

“…The biggest disadvantage of microcapsule-based self-healing systems is the limited number of healing agents, and it is not known when the healing agent will be completely depleted, especially locally, in cases of multiple healing. Multiple healing is only possible if there is an excess of healing agents in the matrix after the first healing has taken place [1,[14][15][16][17].…”

Si/FeSi2 Nanoparticles Prepared by Thermal Plasma with Stress‐releasing Effect for Li‐ion Storage

“…Si as anode materials for Li‐ion batteries (LIBs) have been extensively studied by researchers due to its high theoretical specific capacity, non‐toxic and productive reserves [1–3] . However, the most vital problem of Si materials restricting their commercial LIBs application is the dramatic volume expansion (>300%) during the charge/discharge process [4–6] .…”