Self‐Adapting Electrochemical Grinding Strategy for Stable Silicon Anode

Abstract

The pulverization of silicon during lithiation/delithiation due to its huge volume change results in a loss of electrochemical activity. In this work, advantage is taken of the unavoidable pulverization and an innovative strategy of in-situ self-adapting electrochemical grinding (ECG) is designed for stable silicon anode. MgH 2 is utilized as the grinding aid to electrochemically grind micronsized Si particles. During ECG process, the lithiation processes of MgH 2 and Si occur at different potentials and both result in appreciable volume expansion, leading to a strong internal stress inside the electrode. With this strong internal stress, the lithiation products of MgH 2 , i.e., Mg and LiH, would migrate into the cracked Si particles and gradually transform into a conductive matrix consisting of ionic conductive LiH and electronic conductive via partially reversible lithiation of Mg. After ECG process, micronsized Si particles are spontaneously grinded to an equilibrium size, which can accommodate the volume change and ensure the stable cycling. As prepared Si anode delivers an excellent reversible specific capacity of 3228 mAh g −1 and a capacity retention of 91% after 200 cycles. The proposed in situ self-adapting ECG strategy offers a unique perspective for the development of Si-based anode materials for next-generation lithium ion batteries.

Practical evaluation of prelithiation strategies for next‐generation lithium‐ion batteries

“…Recently, Fang et al achieved a capacity retention of 91% after 200 cycles for a Si anode using Li x Mg and LiH. 23 Lee et al prepared a SiO x /Mg 2 SiO 4 /SiO x composite by a simple combination of the magnesiothermic reduction process and acid treatment, which effectively improves the ICE (from 56.6% to 75.6%) and prevents volume expansion. 24 In addition to using lithium metal as the lithium source, other lithium-containing compounds, such as LiH, 17 have also been developed for prelithiation of Si-based materials (Figure 3B).…”

“…Alternatively, as another method of commercialization, premagnesization treatment of Si‐based materials can also lead to improvements in the ICE and cycling performance. Recently, Fang et al achieved a capacity retention of 91% after 200 cycles for a Si anode using Li x Mg and LiH 23 . Lee et al prepared a SiO x /Mg 2 SiO 4 /SiO x composite by a simple combination of the magnesiothermic reduction process and acid treatment, which effectively improves the ICE (from 56.6% to 75.6%) and prevents volume expansion 24 …”

Recent progress in zeolitic imidazolate frameworks (ZIFs)-derived nanomaterials for effective lithium polysulfide management in lithium–sulfur batteries

“…On the other hand, various alloy/conversion-type electrodes, such as some elements and their compounds of IV A to VII A groups ( e.g. Si, 21 Sn, 22 Sb, 23 Ge, 24 red P, 25 O 2 (air), 26 S, 27 I 2 , 28 and their compounds), 29 have inherently higher theoretical energy density than typical LIBs based on different electrochemistry, thus attracting extensive research interest. Frustratingly, however, batteries based on these metals still face a series of problems caused by larger ionic radii.…”

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

“…First of all, the nanocrystallization and compound strategies of silicon‐based anode materials are developing vigorously, exploring various anode composites with different morphology and structure, including porous silicon, hollow nanospheres, silicon nanowires and so on, which further improve the utilization rate of active substance silicon during cycling. [ 10 , 11 , 12 , 13 ] In addition, the construction of silicon‐based anodes with the multistage complex structures is also popular, such as core‐shell structure, yolk‐shell, cage structure, layered structure, etc., which can further alleviate the volume expansion and other defects of silicon‐based anodes through the synergistic effect of hierarchical structures. [ 14 , 15 , 16 ] However, it is still impractical to completely replace the graphite owing to the bottleneck of limited energy density and insufficient electrode loading.…”