Tin oxide (SnO2) has a high theoretical capacity (∼782 mA h g-1), but it experiences large volume changes during charge and discharge cycles that cause rapid capacity fade, which limits its practical use as an anode material. In an attempt to solve this, we coated these particles with ultrathin electrochemically active iron oxide (FeOx) films that act as an artificial solid electrolyte interphase layer, thus stabilizing the SnO2 particles for better longevity of significantly improved performance at high current densities in a practical voltage window. Since there exists a tradeoff between species transport and protection of particles (expecting long life), a film with an optimum thickness was achieved by atomic layer deposition (ALD) of FeOx on SnO2 particles. With an optimum thickness of about 0.24 nm after 20 cycles of iron oxide ALD (20Fe), an initial capacity of ∼658 mA h g-1 was achieved at a high current density of 1250 mA g-1. After 1000 cycles of charge/discharge at 1250 mA g-1, the 20Fe sample showed a capacity retention of 94% as compared to 52% of the uncoated sample when cycled at room temperature; at 55°C, the capacity retention of the 20Fe sample was 93% compared to 33% of the uncoated sample.


Chemical and Biochemical Engineering


This work was supported in part by the National Science Foundation grant NSF CBET 1510085.

Keywords and Phrases

Anodes; Atomic Layer Deposition; Current Density; Electrolytes; Electron Emission; Iron; Oxide Films; Solid Electrolytes; Tin Oxides; Ultrathin Films; Capacity Retention; Charge and Discharge; Charge/Discharge; High Current Densities; Optimum Thickness; Solid Electrolyte Interphase; Species Transport; Theoretical Capacity; Iron Oxides

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Document Type

Article - Journal

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Final Version

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© 2016 Royal Society of Chemistry, All rights reserved.

Publication Date

01 Feb 2016