The fundamental kinetics of the electrocatalytic sulfur reduction reaction (SRR), a complex 16-electron conversion process in lithium-sulfur batteries, is insufficiently explored to date. Herein, by directly profiling the activation energies in the multi-step SRR, we reveal that the initial reduction of sulfur to the soluble polysulfides is relatively easy with low activation energy, while the subsequent conversion of the polysulfides into the insoluble Li 2 S 2 /Li 2 S is more difficult with much higher activation energy, which contribute to the accumulation of polysulfides and exacerbate the polysulfide shuttling effect. We use heteroatom-doped graphene as a model system to explore electrocatalytic SRR. We show nitrogen and sulfur dual-doped graphene considerably reduces the activation energy to improve SRR kinetics. Density functional calculations confirm that the doping tunes the p-band center of the active carbons for an optimal adsorption strength of intermediates and electroactivity. This study establishes electrocatalysis as a promising pathway to high performance lithium-sulfur batteries. The sulfur reduction reaction (SRR) in lithium-sulfur (Li-S) chemistry undergoes a complex 16-electron conversion process, transforming S 8 ring molecules into a series of soluble lithium polysulfides (LiPSs) with variable chain lengths before fully converting them into 2 insoluble Li 2 S 2 /Li 2 S products. This 16-electron SRR process is of considerable interest for high-density energy storage with theoretical capacity of 1672 mAh g-1 , but the chemistry is plagued by sluggish sulfur reduction kinetics and polysulfide (PS) shuttling effect. In practical Li-S cells, these effects limit the rate capability and cycle life 1,2. These limitations are fundamentally associated with the slow and complex reduction reaction involving S 8 ring molecules. In general, the insulating nature of elemental sulfur and its reduced products, and the sluggish charge transfer kinetics lead to incomplete conversion of S 8 molecules to soluble LiPSs. These polysulfides may shuttle across the separator to react with and deposit on the lithium anode, resulting in rapid capacity fading 3. Considerable efforts have been devoted to combating the PS shuttling effect, typically by employing a passive strategy by using various sulfur host materials to physically or electrostatically trap the LiPSs in the cathode structure 4-13. These passive confinement/entrapping strategies have partly mitigated the PS shuttling

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