Cooperative Lithium Sorption in Doped Layered Double Hydroxides Is Modulated by Colloidal (Dis)Assembly

Abstract

Lithium−aluminum layered double hydroxides (LDHs) selectively sorb lithium from brines, concentrating and purifying this critical element for subsequent conversion to active battery components. Lithium ion partitioning into lattice vacancies within the LDH structure is selectively enhanced with iron doping. However, this process leads to a highly coupled set of intercalation interactions whose mechanisms are challenging to assess in situ.Here, we show that iron modulates the size-and shape-dependent composition of LDHs and imposes a powerful control on lithium sorption processes in complex fluids. We observe fundamental units of LDH layers and aluminum ferrihydrite nanoclusters that (dis)assemble to form at least five distinct particle types that influence LDH lithium capacity and cyclability. Importantly, lithium sorption is controlled by feedbacks arising from the dynamic interconversion of planar stacks and scrolls of LDH layers, which exchange lithium, water, and other species in the process of (un)rolling due to similar energy scales of hydration, sorption, and deformation. Under appropriate iron redox conditions, the cycling efficiency and stability of lithium sorption can be optimized for the range of lithium concentrations found in many natural brines.

Effect of Anions on the Delithiation of [Li–Al] Layered Double Hydroxides: Thermodynamic Insights

“…A higher water content may weaken the interactions, as the anions and water molecules would be more loosely bound in the interlayer space. The recent report by Li et al and Whittaker et al discuss the possibility of phase and morphological changes in the [Li–Al] LDH upon hydration and how it impacts the lithiation and delithiation process . Consequently, the ΔH° f,bc values of Cl-LDH-O, OH-LDH-O, and SO 4 -LDH-O are more exothermic compared to Cl-LDH-A, OH-LDH-A, and SO 4 -LDH-A (Table ).…”

An Antisolvent Extraction Strategy for Extrusion Granulation Enhancement of Aluminum-Based Lithium Adsorbent Used in Ultrahigh Mg2+/Li+ Salt Lake Brines

“…Lithium has seen a constant increase in demand with the rapid promotion of electric vehicles and the vigorous development of energy storage technology worldwide. − Lithium recovery from brines is relatively feasible from economic and environmental considerations, which has attracted enormous interest from researchers in recent decades. − The adsorption method of extracting lithium is particularly suitable for low-lithium-grade brines with an ultrahigh Mg 2+ /Li + mass ratio that is far more than 20 because it is highly selective, simple, low cost, and environmentally friendly. − Up to date, the aluminum-based lithium adsorbents, lithium/aluminum-layered double hydroxides (Li/Al-LDHs), are the first successfully industrialized adsorbents used in brines for lithium recovery, attributing to their desorption properties without solubility loss. − Li/Al-LDHs are typical two-dimensional structures and consist of positively charged host layers formed by Al–O octahedra and linked by hydrogen bonds with anions and water molecules sandwiched. Lithium cations exist in the holes of the hydroxide layers composed of the Al–O octahedral without forming chemical bonds with other elements. , …”