Fig. 3: Mechanism for enhancement of Li⁺ extraction.

a The Li⁺ extraction capacity (Q_e) comparison in the dark. The initial conditions: 298 K, pH = 10, the concentrations of Li⁺ solution is 25 ppm. b Differential charge and binding energy between LMO (or HMO) and PPH. c The schematic diagram of lithium adsorption enhanced by swelling process (left), and simulated Li⁺ distribution in the channels of HMO@PPH with different swelling properties (Right). d The Li⁺ extraction capacity (Q_e) of HMO@PPH based on hydrogel weight. e The Li⁺ extraction capacity (Q_e) of HMO@PPH based on HMO weight. The horizontal dotted line is the Li⁺ adsorption capacity of HMO powders. f The Li⁺ distribution in APIP under the different conditions: (I) in the dark and (II) under 1 sun illumination, as simulated in COMSOL software. g TEF at different locations in APIP obtained by COMSOL software. h Theoretical Li⁺ adsorption concentration of APIP under different solar fluxes obtained by COMSOL software. The dotted line refers to the Li⁺ saturated adsorption concentration by APIP.