Electrodeposition of Atmosphere-Sensitive Ternary Sodium Transition Metal Oxide Films for Sodium-Based Electrochemical Energy Storage

Layered sodium transition metal oxides constitute an important class of materials with applications including electrochemical energy storage, high temperature superconductivity and electrocatalysis. However, electrodeposition of these compounds, an approach commonly used to grow other oxides, has been elusive due to their atmosphere instability and intrinsic incompatibility with aqueous electrolytes. Through use of a dry molten sodium hydroxide electrolyte, we demonstrate the high throughput electrodeposition of O3 (O’3) and P2 type layered sodium transition metal oxides across multiple transition metal chemistries, and apply these electrodeposits as high areal capacity cathodes in sodium-ion batteries. The electrodeposits are microns thick, polycrystalline, and structurally similar to materials synthesized classically at high temperature. This work enables fabrication of a wide group of previously inaccessible alkali and alkaline earth ion intercalated, higher valent transition group oxides in important thick film form factors.