PRZMBs · Development of full-range energy band matching photo-recharged Zn metal batteries

The full-range energy band matching (FEBM) photo-recharged Zn metal batteries (PRZMBs) that can convert solar energy into electrochemical energy in one step are considered a totally clean energy system, which can not only avoid the usage of harmful substances (Cr, Pb, etc.) in solar cells and reduce the usage of fossil fuels but also reduce the cost of large-scale power grids. In this proposal, based on low-cost, environmentally friendly aqueous zinc metal batteries, a modified MoS2 material (m-MoS2) will be employed as a photocathode by O substitution for partial S to increase the layer spacing and improve the electrochemical activity of m-MoS2 (WP1). The electrochemical reaction process and kinetics will be studied by the precise control of the structure, morphologies, and O contents in m-MoS2 to realize the aim of a capacity improvement of 100 mAh g-1 at 100 mA g-1 compared with original MoS2. Subsequently, a precursor solid method will be employed to synthesize the m-MoS2/fCNTs composites with a covalent bonding interface, which can avoid structural collapse during the cycling process and effectively improve the reversibility, and finally to realize the goal of operation time over 1000 hours (WP1). Based on the tunability of layered MoS2, the relations between layers, O contents of m-MoS2, and energy band structure will be studied to provide the foundation for the FEBM process. Finally, based on the results from WP1-2, the energy band changes of m-MoS2 during cycling will be studied to screen out the proper energy band range of m-MoS2 to construct a FEBM photoelectrode. In addition, the relationship between the photogenerated charge and the electrochemical reaction mechanism (reaction kinetics, intercalation/phase conversion, and capacitive behavior) will be investigated to finally realize a high-performance PRZMB with high power/energy densities by increasing the photoelectric conversion efficiency and photo-charging rate over 10% and 30 mA g-1.