Alberto Battistel

Batteries for lithium recovery from brines

Here, we report a new battery capable of efficiently recovering lithium from brines that is composed of a lithium-capturing cationic electrode (LiFePO4) and a chloride-capturing anionic electrode (Ag). It can convert a sodium-rich brine (Li : Na = 1 : 100) into a lithium-rich solution (Li : Na = 5 : 1) by consuming 144 W h per kg of lithium recovered.

Selectivity of a Lithium‐Recovery Process Based on LiFePO4

The demand for lithium will increase in the near future to 713,000 tonnes per year. Although lake brines contribute to 80% of the production, existing methods for purification of lithium from this source are expensive, slow, and inefficient. A novel electrochemical process with low energy consumption and the ability to increase the purity of a brine solution to close to 98% with a single-stage galvanostatic cycle is presented.

Nickel Hexacyanoferrate as Suitable Alternative to Ag for Electrochemical Lithium Recovery

Currently, Li is mainly produced through evaporation of Li-rich brines obtained from South American countries such as Bolivia, Chile, and Argentina. The most commonly used process, the lime-soda evaporation, requires a long time and several purification steps, which produces a considerable amount of chemical waste. Various electrochemical methods have been proposed as alternatives, but they use expensive metals such as Ag or Pt, thus rendering these methods economically unacceptable. In this work, we present KNiFe(CN)6 , an abundant and environmentally friendly material, as alternative to these expensive components. The Prussian blue derivate has a higher affinity toward cations (Na(+) or K(+) ) than for Li(+) . Additionally, the use of KNiFe(CN)6 permits the utilization of seawater or brine water as recovery solution, thus reducing the consumption of fresh water, which is typically a scarce element in Li production sites.

Impact of single basepair mismatches on electron-transfer processes at Fc-PNA⋅DNA modified gold surfaces.

Gold-surface grafted peptide nucleic acid (PNA) strands, which carry a redox-active ferrocene tag, present unique tools to electrochemically investigate their mechanical bending elasticity based on the kinetics of electron-transfer (ET) processes. A comparative study of the mechanical bending properties and the thermodynamic stability of a series of 12-mer Fc-PNA⋅DNA duplexes was carried out. A single basepair mismatch was integrated at all possible strand positions to provide nanoscopic insights into the physicochemical changes provoked by the presence of a single basepair mismatch with regard to its position within the strand. The ET processes at single mismatch Fc-PNA⋅DNA modified surfaces were found to proceed with increasing diffusion limitation and decreasing standard ET rate constants k(0) when the single basepair mismatch was dislocated along the strand towards its free-dangling Fc-modified end. The observed ET characteristics are considered to be due to a punctual increase in the strand elasticity at the mismatch position. The kinetic mismatch discrimination with respect to the fully-complementary duplex presents a basis for an electrochemical DNA sensing strategy based on the Fc-PNA⋅DNA bending dynamics for loosely packed monolayers. In a general sense, the strand elasticity presents a further physicochemical property which is affected by a single basepair mismatch which may possibly be used as a basis for future DNA sensing concepts for the specific detection of single basepair mismatches.

Using Cavity Microelectrodes for Electrochemical Noise Studies of Oxygen‐Evolving Catalysts

Cavity microelectrodes were used as a binder-free platform to evaluate oxygen evolution reaction (OER) electrocatalysts with respect to gas bubble formation and departure. Electrochemical noise measurements were performed by using RuO2 as a benchmark catalyst and the perovskite La0.58 Sr0.4 Fe0.8 Co0.2 O3 as a non-noble metal OER catalyst with lower intrinsic conductivity. Changes in the current during the OER originate from variations in electrolyte resistance during the formation of the gas phase and partial coverage of the active area. Fluctuations observed in current and conductance transients were used to establish the contribution from the ohmic overpotential and to determine the characteristic frequency of oxygen evolution. The proposed quantitative determination of gas bubble growth and departure opens up the route for a rational interface design by considering gas bubble growth and departure as a main contributing factor to the overall electrocatalytic activity at high current densities.

Nonlinear analysis: the intermodulated differential immittance spectroscopy.

Intermodulation is used for the analysis of the nonlinear behavior of electrochemical and electronic systems. As a matter of fact, different than the passive elements, electrochemical systems have a highly nonlinear character, which can be used to obtain information on the reaction mechanism and structure of the double layer. The setup for measuring and analyzing the intermodulated sidebands is discussed in detail, using a commercial Schottky diode as the ideal system. A general intermodulated differential immitance spectroscopy technique was consequently defined as the analysis of the variation of the immittance elements as a function of the stimulus frequency, and its transfer function was called differential immittance spectrum. Through a simple model, it was possible to precisely calculate the flat band voltage and the doping level of the Schottky diode from a single differential immittance spectrum. The differential immitance spectra of a dummy cell containing passive elements demonstrated the resolution limits of the technique.