Effect of chemistry and geometry of GO nanochannels on the Li ion selectivity and recovery

The continually increasing demand for lithium (Li) is predicted to soon exceed its availability, rendering it a geopolitically significant resource. Although seawater is considered one of the largest Li resources, the coexistence of Li ion (Li⁺) with chemically similar ions such as Na⁺ and K⁺ in seawater and its low concentration makes the Li⁺ extraction from this resource very challenging. Here, the chemical and morphological characterization of graphene traps for maximum lithium-ion capture was introduced by using a theoretical approach. The results illustrate the effect of the key parameters including interlayer spacing and length, surface charge, and functional group, and nanochannel morphology on Li⁺ selectivity, which results in the cavities with innovative intrinsic traps. These cavities benefit from cation-π interactions, the ability to control interlayer spacing based on the functional group, and a variable energy barrier. The improvements in Li⁺ selectivity in functionalized asymmetrical graphene nanochannels has been demonstrated, providing new insights for Li⁺ selective material design.