Nanostructured Sn-Mo multilayer film anode with stable electrode-interfaces for long-cycle lithium storage

Sn has emerged as an alternative anode material which involves alloying reactions toward Li storage. However, its huge volume and structural changes lead to severe degradation of the electrode and cumulative thickening of the solid electrolyte interface (SEI) upon cycling, which dramatically shorten the cycle life of the electrode. Here, we demonstrate that in the rationally designed interface structure of Sn-Mo film electrodes, with the addition of Mo protective layers and the well-dispersed dot-like Mo nanoparticles in the Sn-Mo layer, the highly stable electrode-interfaces and improved electrochemical performance can be achieved. The Mo/Sn-Mo/Mo multilayered electrode exhibits an initial reversible capacity of 870 mA h g-1, and maintains a capacity retention of 70% after 400 cycles between 0.01 and 2 V vs. Li/Li+, much superior to those previous reported Sn-based alloy thin film anodes. Besides, the Mo/Sn-Mo/Mo electrode can achieve 540 mA h g-1 after 200 cycles within 0.01-1.2 V on both copper foil and carbon film current collectors, and has superior stable reversible capacities within 0.2-1.2 V and 0.01-0.8 V. This work based on interfacial modification provides a fundamental strategy to design electrode materials for large capacity and flexible lithium-ion batteries.

Automated summary

The insertion of Mo protective layers and well-dispersed Mo nanoparticles in Sn-Mo film electrodes creates highly stable electrode-interfaces, leading to improved electrochemical performance and long cycle life. The Mo/Sn-Mo/Mo multilayered electrode demonstrates superior reversible capacity and capacity retention compared to previous Sn-based alloy thin film anodes, showcasing the potential for designing electrode materials for large capacity and flexible lithium-ion batteries through interfacial modification.