Related Experiment Video
Updated: Dec 9, 2025
Electrochemically and Bioelectrochemically Induced Ammonium Recovery
Published on: January 22, 2015
Facile Proton Transport in Ammonium Borosulfate-An Unhumidified Solid Acid Polyelectrolyte for Intermediate
Matthew D Ward1, Brian L Chaloux1, Michelle D Johannes2
1Chemistry Division, US Naval Research Laboratory, Washington, DC, 20375, USA.
Abstract:
High proton conductivity is reported for unhumidified ammonium borosulfate, NH4 [B(SO4 )2 ], a solid acid coordination polymer that contains 1D, hydrogen-bonded NH4 + ···1 ∞ [B(SO4 )4/2 ]- chains. NH4 [B(SO4 )2 ] is thermally stable to 320 °C and is amenable to sintering into monolithic, polycrystalline discs at 200 °C and about 300 MPa of uniaxial pressure. Impedance spectroscopy measurements reveal ionic conductivities for sintered ammonium borosulfate of 0.1 mS cm-1 at 25 °C and up to 10 mS cm-1 at 180 °C in ambient air. No superprotonic transition is observed in the temperature range of 25-180 °C. Ab initio molecular dynamics simulations show these high conductivities are aided by free rotation of the NH4 + units and significant gyrational mobility of the SO4 tetrahedra, which, in turn, provide facile pathways for proton locomotion. High conductivities, a wide operational temperature window, and tolerance to both ambient and anhydrous conditions make NH4 [B(SO4 )]2 an attractive candidate electrolyte for intermediate-temperature hydrogen fuel cells that may enable operation at temperatures as high as 300 °C without active humidification.
More Related Videos
Related Concept Videos
03:21Weak Base Solutions
01:20Titration of a Weak Base with a Strong Acid
Using the ICE table and substituting the Kb value, we calculate the initial pH of 50 mL of 0.1 M ammonia to be 11.11. Addition of 25 mL of 0.1 M hydrochloric acid to this solution of ammonia results in a buffer with an equal concentration of ammonia and ammonium ions. The pH of this buffer can be calculated by substituting these...
02:54Ions as Acids and Bases
Salts are ionic compounds composed of cations and anions, either of which may be capable of undergoing an acid or base ionization reaction with water. Aqueous salt solutions, therefore, may be acidic, basic, or neutral, depending on the relative acid-base strengths of the salt’s constituent ions. For example, dissolving the ammonium chloride in water results in its dissociation, as described by the equation:
03:24Common Ion Effect
01:21Basicity of Aliphatic Amines
To measure the basicity of amines, two conventions are generally used. The first defines Kb as the basicity constant for the deprotonation reaction of water by the amine, as presented in Figure 1. Conventionally, lower Kb indicates higher...
01:16Titration in Nonaqueous Solvents