Reversible electrochemical conversion from selenium to cuprous selenide

Abstract

Cu2+/Cu+ ion is reversibly hosted via the sequential conversion reactions of Se  CuSe  Cu3Se2  Cu2Se. The four-electron redox process from Se to Cu2Se produces a high initial...

Ball Milling-Enabled Fe2.4+ to Fe3+ Redox Reaction in Prussian Blue Materials for Long-Life Aqueous Sodium-Ion Batteries

“…To understand the fundamental reason for the high stability, the redox reaction mechanism upon Na-insertion/desertion was investigated through X-ray absorption fine edge structure (XANES) at the Fe K-edge which provides oxidation state and local structure information. − It is natural that the Na-ion insertion/extraction will result in the oxidation state of Fe in the PBA framework to change. ,, In the fully filled framework, Prussian white (Na 2 Fe­[Fe­(CN) 6 ]), the theoretical oxidation state of Fe is 2+. When Na-ions are extracted the oxidation state of Fe increases, in the case of a half-filled (NaFe­[Fe­(CN) 6 ]) and empty (Fe­[Fe­(CN) 6 ]) framework, the average oxidation states of Fe are 2.5+ and 3+, respectively.…”

“…31−34 It is natural that the Na-ion insertion/extraction will result in the oxidation state of Fe in the PBA framework to change. 26,31,35 In the fully filled framework, Prussian white (Na 2 Fe[Fe(CN) 6 ]), the theoretical oxidation state of Fe is 2+. When Na-ions are extracted the oxidation state of Fe increases, in the case of a half-filled (NaFe[Fe(CN) 6 ]) and empty (Fe[Fe(CN) 6 ]) framework, the average oxidation states of Fe are 2.5+ and 3+, respectively.…”

From Copper to Basic Copper Carbonate: A Reversible Conversion Cathode in Aqueous Anion Batteries

“…To understand the electrode compositions, ex situ X-ray absorption near edge structures (XANES) of the X-ray absorption (XAS) studies were collected at various SOC. [26][27][28][29][30] For the fully charged electrode, the XANES results are compared with possible products of copper oxidation in an aqueous environment, where the major peak at 8998 eV of the charged electrode corresponds to cupric phases (Figure 3A), and linear combination fitting (LCF) identifies both Cu 2 CO 3 (OH) 2 (42.1 %) and CuO (57.8 %) as the major contributors (Figure S3). CuO may come from the native oxide layer and sample handling, which explains its high percentage.…”

Ultra-stable Cu-ion-exchanged cobalt hexacyanoferrate(ii) in aqueous copper-ion storage

“…Additionally, the organic solvents employed in LIBs are highly flammable, showing safety issues. [6][7][8][9][10] Consequently, batteries with aqueous electrolytes are selected as alternatives to LIBs for addressing these concerns, and several systems have been proposed to date, e.g., aqueous monovalent-ion batteries (aqueous sodium-ion batteries 11,12 and aqueous potassium-ion batteries (APIBs) [13][14][15] ), aqueous multivalent-ion batteries (aqueous magnesium-ion batteries, [16][17][18] aqueous zinc-ion batteries (AZIBs), [19][20][21] and aqueous copper-ion batteries (ACIBs) [22][23][24][25][26][27][28] ). As a member of aqueous multivalent-ion batteries, ACIBs exhibit advantages such as high capacity, low cost, and eco-friendliness, and are thus enjoying wide interest.…”