Fundamental Understanding and Facing Challenges in Structural Design of Porous Si‐Based Anodes for Lithium‐Ion Batteries

Abstract

As one of the most electrochemical energy storage devices, lithium-ion batteries (LIBs) remain the workhorse of the energy market due to their unparalleled advantages. Remarkably, Si-based materials play a pivotal role in LIBs anodes owing to ultrahigh theoretical capacity of Si and rich natural resources. However, bulk silicon materials are difficult to meet the current commercial demand because of their low conductivity, sluggish reaction kinetics, and huge volume expansion. The construction of porous structures has been acknowledged as an effective way to solve the above issues. Herein, the delicate design of porous Si-based anode materials including synthetic strategies, the engineering of surface morphology and micro/nano-structure, and the regulation of different compositions, as well as their applications in LIBs is systematically summarized. Particularly, the fine engineering of different pore parameters for Si-based materials is on focus. Importantly, the relationship between thick electrodes and tortuosity/porosity, and the structural effect between pores and battery performance are also discussed in depth. Finally, the applications of porous Si-based anodes in full-cells and their commercial achievements are briefly described. This review is expected to provide a basic understanding and deep insight into developing porous Si-based anodes for high-energy lithium storage.

A Three-Dimensional Fiber-Network-Reinforced Composite Solid-State Electrolyte from Waste Acrylic Fibers for Flexible All-Solid-State Lithium Metal Batteries

“…At 0.2–1.0 C, the charge–discharge curve is smooth and the polarization voltage is small. When the current density increases to 2 C, the polarization voltage also increases slightly, indicating the low internal impedance of the electrolyte and faster reaction kinetics. , Figure e displays the rate performance of the LFP | 15LLZTO/acrylic | Li battery. At current densities of 0.2, 0.3, 0.5, 1.0, and 2 C, the average discharge specific capacities are 159.06, 152.38, 133.48, 104.08, and 74.25 mAh g –1 , respectively.…”

“…When the current density increases to 2 C, the polarization voltage also increases slightly, indicating the low internal impedance of the electrolyte and faster reaction kinetics. 72,73 S13a,b). Importantly, when the current density is restored to 0.2 C, the discharge specific capacity of the LFP | 15LLZTO/acrylic | Li battery returned to 155.75 mA h g −1 , further demonstrating the reversibility and stability of this ASSLMB.…”

Constructing Pure Si Anodes for Advanced Lithium Batteries

“…The porous structure evolved with the subsequent strain-etching process, using different etchants that influenced the degrees of porosity. A highly porous structure throughout the entire particle showed even better cycling performance, as sufficient pores reduce the bottleneck effect of Li-ion accumulation on the surface . Notably, the plentiful pores and void spaces can alleviate the spatially volumetric change at both particle and electrode levels, minimizing the external and internal stresses that lead to irreversible deformation and consequently reinforcing structural integrity.…”

“…A highly porous structure throughout the entire particle showed even better cycling performance, as sufficient pores reduce the bottleneck effect of Li-ion accumulation on the surface. 26 Notably, the plentiful pores and void spaces can alleviate the spatially volumetric change at both particle and electrode levels, minimizing the external and internal stresses that lead to irreversible deformation and consequently reinforcing structural integrity. While a highly porous structure displayed superior resilience to crack formation and pulverization, challenges with the unstable SEI layer persist.…”

ZIF-8-Derived Carbon In-Situ Encapsulated Hollow Mn2SiO4 Sub-Microspheres as Anode for Lithium-Ion Batteries with Ultrahigh Capacity and Excellent Rate Performance

“…As for the exploitation and utilization of bright lithium ion batteries (LIBs), it is of great significance for excavation of novel anode materials with enhancing performance. − As an ideal anode material with the potential to replace graphite (375 mA h g –1 ), silicon has an impressive theoretical capacity (∼4200 mA h g –1 ) and exceptional abundance . Nevertheless, the pulverization, collapse, and destruction of the microstructure are often caused by the large volume expansion (∼400%) of pure silicon anode materials, resulting in inefficient cycle life.…”