This work provides a general design rule as the selection criteria of metal-cation dopants to tune their catalytic activity for designing advanced Li-S catalysts. As expected, V-doped WSe2/MXene catalyst with a minimum EA/r value as a high-efficiency sulfur host exhibits the highest reversible capacity (1402.5 mAh g-1), a long-term cycling stability with 800 cycles (~70% retention), and a large areal capacity (6.4 mAh cm-2). To complete this calculation, you have to know what substance you. A common request on this site is to convert grams to moles. The formula weight is simply the weight in atomic mass units of all the atoms in a given formula. Theoretical and experimental results reveal that a low EA/r value of metal-cation dopant easily induces more Se vacancies and lattice defects, increases active sites and more electron accumulation on surface Se sites for stronger binding with lithium polysulfides (LiPSs), but it also weakens the competing Li-S bonds in LiPSs/Li2S captured on host surface, thereby increasing LiPSs adsorption yet decreasing Li2S nucleation and decomposition energy barrier. When calculating molecular weight of a chemical compound, it tells us how many grams are in one mole of that substance. And a series of metal-cation dopants with different EA/r values into WSe2 as a model to engineer their electronic structure and catalytic activity for manipulating sulfur redox kinetics are systematically investigated. Herein, we demonstrate a general electron affinity/ionic radius (EA/r) rule as a new selection criterion of metal-cation dopants to guide the design of efficient metal-cation-doped Li-S catalysts. Despite metal-cation doping into transition-metal dichalcogenides (TMDCs) has been investigated for promoting stepwise sulfur redox in lithium-sulfur batteries (LSBs), a rational design principle and systematic theoretical study on how to select a suitable metal-cation dopant into TMDCs to tune their catalytic activity are lacking in LSBs.
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