Novel LiAlO2 Material for Scalable and Facile Lithium Recovery Using Electrochemical Ion Pumping

In this study, α-LiAlO2 was investigated for the first time as a Li-capturing positive electrode material to recover Li from aqueous Li resources. The material was synthesized using hydrothermal synthesis and air annealing, which is a low-cost and low-energy fabrication process. The physical characterization showed that the material formed an α-LiAlO2 phase, and electrochemical activation revealed the presence of AlO2* as a Li deficient form that can intercalate Li+. The AlO2*/activated carbon electrode pair showed selective capture of Li+ ions when the concentrations were between 100 mM and 25 mM. In mono salt solution comprising 25 mM LiCl, the adsorption capacity was 8.25 mg g−1, and the energy consumption was 27.98 Wh mol Li−1. The system can also handle complex solutions such as first-pass seawater reverse osmosis brine, which has a slightly higher concentration of Li than seawater at 0.34 ppm. © 2023 by the authors.This study is made possible by Qatar National Research Fund (QNRF) under National Priorities Research Program (NPRP) grant (#NPRP12S-0227-190166) and Graduate Student Research Award (GSRA) grant (#GSRA8-L-2-0411-21011).Scopu

Electrochemical system design for CO2 conversion: A comprehensive review

This paper reviews the electrochemical reduction of CO2 and the design of CO2 electrolyzer cells using advanced materials and novel configurations to improve efficiency and reduce costs. It examines various system types based on geometry and components, analyzing key performance parameters to offer valuable insights into effective and selective CO2 conversion. Techno-economic analysis is employed to assess the commercial viability of electrochemical CO2 reduction (eCO2R) products. Additionally, the paper discusses the design of eCO2R reactors, addressing challenges, benefits, and developments associated with reactant supply in liquid and gas phases. It also explores knowledge gaps and areas for improvement to facilitate the development of more efficient eCO2R systems. To compete with gas-fed electrolyzers, the paper presents various approaches to enhance the performance of liquid-fed electrolyzers, leveraging their operation simplicity, scalability, low costs, high selectivity, and reasonable energy requirements. Furthermore, recent reports summarizing the performance parameters of reliable and effective electrocatalysts under ideal operating conditions, in conjunction with different electrolyzer configurations, are highlighted. This overview provides insights into the current state of the field and suggests future research directions for producing valuable chemicals with high energy efficiency (low overpotential). Ultimately, this review equips readers with fundamental knowledge and understanding necessary to improve and optimize eCO2R beyond lab-scale applications, fostering advancements in the promising field.This publication was made possible by the Qatar National Research Fund (a member of Qatar Foundation) under NPRP grant ( NPRP13S-0202-200228 ). H.P. is grateful to the National Research Foundation of Korea ( RS-2023-00254645 , 2018R1A6A1A03024962 , and 2021K1A4A7A02102598 ) and the Korea Evaluation Institute of Industrial Technology (Alchemist Project 20018904 , NTIS-1415180111 ) through the Ministry of Trade, Industry, and Energy, Korea.Scopu

Polyzwitterionic Hydrogels in Engines Based on the Antipolyelectrolyte Effect and Driven by the Salinity Gradient

In this paper, we propose and investigate an original approach to energy conversion based on polyzwitterionic hydrogels, which exhibit an antipolyelectrolyte effect that enables them to swell in salt water and shrink in water of a different (i.e., desalinated water) salinity. The swelling and shrinking processes run cyclically and can move a piston up or down reversibly, thus transforming the antipolyelectrolyte effect into a mechanical force based on the salinity gradient. This phenomenon makes polyzwitterionic hydrogels suitable for use in a smart, polymeric engine. We apply this approach to investigate energy recovery from a polysulfobetaine-based hydrogel. The cross-linking density, external load, particle size, and repeatability of energy recoverability of hydrogels are examined. The maximum energy recovery from 0.4 g of hydrogel in feed (calculated based on dry form) of 102 mJ/kg was obtained by a hydrogel with a 3% cross-linking density, a 200-300 ?m particle size, and 100 g external load. Excellent reproducibility of engine cycles was achieved over 10 cycles. This concept is complementary to the osmotic engine concept based on a polyelectrolyte hydrogel. In addition, polyzwitterionic materials have become a benchmark material for preventing biofouling, and the swelling properties of such materials can be further modulated and tuned. - 2019 American Chemical Society.This publication was supported by Qatar University grants [QUUG-CAM-2017-1, QUHI-CENG-18/19-1]. The statements made herein are solely the responsibility of the authors.Scopu

Ti3C2Tx mxene-based light-responsive hydrogel composite for bendable bilayer photoactuator

Soft actuators based on hydrogel materials, which can convert light energy directly into mechanical energy, are of the utmost importance, especially with enhancements in device development. However, the hunt for specific photothermal nanomaterials with distinct performance remains challenging. In this study, we successfully fabricated a bilayer hydrogel actuator consisting of an active photothermal layer from incorporated Ti3C2Tx MXene in poly(N-isopropylacrylamide) p(NIPAm)hydrogel structure and a passive layer from the N-(2-hydroxylethylpropyl)acrylamide (HEAA) hydrogel structure. The uniform and effective incorporation of MXene into the NIPAm hydrogel structures were characterized by a battery of techniques. The light responsive swelling properties of the MXene-embedded NIPAm-based hydrogel demonstrated fully reversible and repeatable behavior in the light on?off regime for up to ten consecutive cycles. The effect of MXene loading, the shape of the actuator, and the light source effects on the bilayer NIPAm-HEAA hydrogel structure were investigated. The bilayer hydrogel with MXene loading of 0.3% in the NIPAm hydrogel exhibited a 200% change of the bending angle in terms of its bidirectional shape/volume after 100 s exposure to white light at an intensity of 70 mW cm?2 . Additionally, the bending behavior under real sunlight was evaluated, showing the material's potential applicability in practical environments.Scopu

A review on lithium recovery using electrochemical capturing systems

Resource recovery from natural reserves is appealing and Li extraction from different brines is in the forefront. Li extraction by membranes is reviewed in the literature much more than electrochemical processes. However, a very recent review thoroughly discussed Li recovery by electrochemically switchable ion exchange (ESIX). This paper reviews Li recovery by both charge transfer processes, namely electrodialysis (ED), and electro-sorption processes, namely capacitive deionization (CDI). It also reviews ESIX with a focus on performance matrices and includes comments on the technology readiness of each separation technique. These processes exhibit promising perspectives on the separation and recovery of Li both selectively and non-selectively from simulated brine solutions and Li salt solutions. Readers are provided with guidelines to choose between the processes, depending on the applied voltage, current density, specific energy consumption and purity of recovered Li. Most electrochemical lithium capturing systems (ELiCSs) have been tested at the lab scale. Therefore, future research should be directed toward pilot-scale development and parameter optimization. Furthermore, we urge the ELiCSs research community to report information in a standard form that allows meaningful comparisons and insights into the systems.This publication was made possible by NPRP grant # [NPRP12S-0227-190166] from the Qatar National Research Fund (a member of Qatar Foundation). The findings achieved are solely the responsibility of the authors. Open Access funding provided by the Qatar National Library