Zhang Tong, Chen Chaoda, Bian Xiaofei, Jin Biao, Li Zhenzhen, Xu Hongxia, Xu Yanhui, Ju Yanming
College of Mechanical and Electrical Engineering, Guangdong University of Science and Technology Dongguan 523000 P. R. China.
School of Materials Science and Engineering, Dongguan University of Technology Dongguan 523808 P. R. China.
RSC Adv. 2022 Jul 6;12(30):19678-19685. doi: 10.1039/d2ra02042d. eCollection 2022 Jun 29.
The huge volume expansion of over 300%, dreadful electrical conductivity and labile solid electrolyte interphase (SEI) are the principal reasons of the sluggish development of Si anodes for lithium-ion batteries (LIBs). Therefore, we propose, for the first time, that titanium nitride (TiN) be utilized as a coating layer to fabricate yolk-shell-structured Si@TiN nanoparticles. The design of the yolk-shell structure can reserve excrescent space for the volume expansion of Si electrodes, which helps to mitigate volumetric changes. Moreover, the TiN protecting layer is beneficial to the formation of a stable and flimsy SEI film, avoiding the excessive consumption of electrolytes. Finally, the ultrahigh conductivity (4 × 10 S cm) as well as the high mechanical modulus of TiN can significantly promote charge transfer and avoid the crushing of the SEI film caused by excessive local stress during reduplicative Li deposition/stripping. Accordingly, the Si@TiN composites show excellent electrochemical properties and suppressed volume expansion compared with pure silicon nanoparticles (Si NPs). Here, these yolk-shell-structured Si@TiN nanoparticles exhibit improved rate performance and excellent long cycling stability with 2047 mA h g at 1000 mA g after 180 cycles. This paradigm may provide a feasible engineering protocol to push the properties of Si anodes for next-generation LIBs.
超过300%的巨大体积膨胀、极差的电导率以及不稳定的固体电解质界面（SEI）是锂离子电池（LIBs）硅阳极发展缓慢的主要原因。因此，我们首次提出利用氮化钛（TiN）作为涂层来制备蛋黄壳结构的Si@TiN纳米颗粒。蛋黄壳结构的设计可以为硅电极的体积膨胀预留多余空间，这有助于减轻体积变化。此外，TiN保护层有利于形成稳定且轻薄的SEI膜，避免电解质过度消耗。最后，TiN的超高电导率（4×10 S cm）以及高机械模量能够显著促进电荷转移，并避免在反复的锂沉积/剥离过程中因局部应力过大导致SEI膜破碎。因此，与纯硅纳米颗粒（Si NPs）相比，Si@TiN复合材料表现出优异的电化学性能和抑制的体积膨胀。在此，这些蛋黄壳结构的Si@TiN纳米颗粒在1000 mA g电流密度下循环180次后，展现出改善的倍率性能和优异的长循环稳定性，比容量为2047 mA h g。这种范例可能为推动下一代LIBs硅阳极性能提供一种可行的工程方案。
