Stabilization and improvement of energy storage performance of high mass loading cobalt hydroxide electrode by surface functionalization

Jacob Olchowka (1, 2, 3) , Ronan Invernizzi (1) , Alexia Lemoine (4) , Joachim Allouche (4, 3) , Isabelle Baraille (4) , Delphine Flahaut (4, 3) , Liliane Guerlou-Demourgues (1, 2, 3)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
2 ALISTORE-ERI - Advanced Lithium Energy Storage Systems - ALISTORE-ERI
3 RS2E - Réseau sur le stockage électrochimique de l'énergie
4 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

Nano-oxides and hydroxides generate great interest as promising positive electrode materials for the development of high energy density supercapacitors. However, their usually limited ionic and electronic conductivities significantly decrease their energy storage performances when increasing the electrode's mass loading. Here, we report on a sonochemical approach to functionalize the surface of Co(OH)2 nanomaterials by EmimBF4 ionic liquid that greatly improves the stability and the electrochemical performances of high mass loading electrodes (13 mg cm−2). This surface functionalization boosts the transport properties and strongly enhances the capacity as well as the capacity retention at higher current densities compared to basic Co(OH)2 (e.g. 113.5 C g−1 vs 59.2 C g−1 at 1 A g−1). Additionally, the protective layer formed by the ionic liquid stabilizes the electrode material upon cycling in KOH aqueous electrolyte and protects the material from oxidation upon open-air storage.

Mots clés: Supercapacitors; Electrochemical energy storage; Surface modification; Cobalt hydroxide; Ionic Liquids

Domaines: Matériaux

Jacob Olchowka, Ronan Invernizzi, Alexia Lemoine, Joachim Allouche, Isabelle Baraille, et al.. Stabilization and improvement of energy storage performance of high mass loading cobalt hydroxide electrode by surface functionalization. Journal of The Electrochemical Society, 2020, 167 (10), 100527 (7 p.). ⟨10.1149/1945-7111/ab9a03⟩. ⟨hal-02972539⟩