Nano-vault architecture mitigates stress in silicon-based anodes for lithium-ion batteries

M. Haro, P. Kumar, J. Zhao, P. Koutsogiannis, A. J. Porkovich, Z. Ziadi, T. Bouloumis, V. Singh, E. J. Juarez-Perez, E. Toulkeridou, K. Nordlund, F. Djurabekova, M. Sowwan, P. Grammatikopoulos, Nano-vault architecture mitigates stress in silicon-based anodes for lithium-ion batteries, Communications Materials 2021, 2, 16

Nanomaterials undergoing cyclic swelling-deswelling benefit from inner void spaces that help
accommodate significant volumetric changes. Such flexibility, however, typically comes at a
price of reduced mechanical stability, which leads to component deterioration and, even-
tually, failure. Here, we identify an optimised building block for silicon-based lithium-ion
battery (LIB) anodes, fabricate it with a ligand- and effluent-free cluster beam deposition
method, and investigate its robustness by atomistic computer simulations. A columnar
amorphous-silicon film was grown on a tantalum-nanoparticle scaffold due to its shadowing
effect. PeakForce quantitative nanomechanical mapping revealed a critical change in
mechanical behaviour when columns touched forming a vaulted structure. The resulting
maximisation of measured elastic modulus (~120 GPa) is ascribed to arch action, a well-
known civil engineering concept. The vaulted nanostructure displays a sealed surface resis-
tant to deformation that results in reduced electrode-electrolyte interface and increased
Coulombic efficiency. More importantly, its vertical repetition in a double-layered aqueduct-
like structure improves both the capacity retention and Coulombic efficiency of the LIB