Conversion-type metal sulfide anode with high theoretical capacity has received increasing attention in Na-ion batteries (SIBs), but the irreversible conversion of Na2S intermediate in charging process usually engenders low rate capability and poor cycling stability. Herein, guided by DFT calculation, a new-type carbonaceous graphitic carbon nitride (g-CN) catalyst is first reported to boost conversion kinetics of Na2S intermediate to pristine MoS2 in SIBs. Notably, the large chemisorbed energy, high selectivity and low catalytic energy barrier of g-CN catalyst can ensure its affluent charge transfers to Na2S intermediate, which chemically anchor and decompose Na2S intermediate for catalyzing its reversible conversion. Moreover, the microfluidic strategy is developed to enhance the mass diffusion of g-CN catalyst precursors into MoS2 skeleton for facilitating their subsequently covalent bonding process. The covalent bonding of g-CN catalyst on 1T-MoS2 (1T-MoS2/g-CN) superlattice with strong interfacial interaction via C-Mo bond can greatly promote Na+-storage kinetics of MoS2 in discharging process and reversible conversion reaction of Na2S intermediate to pristine MoS2 in following charging process, which is further evidenced by DFT calculation and in-situ characterizations. Consequently, the 1T-MoS2/g-CN superlattice reveals superb rate capacity and excellent cycling stability.

中文翻译：

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碳质催化剂促进 Na2S 在 Na 离子电池中的转化动力学


具有高理论容量的转换型金属硫化物负极在钠离子电池 （SIB） 中越来越受到关注，但 Na2S 中间体在充电过程中的不可逆转换通常会导致倍率能力低且循环稳定性差。在此，以 DFT 计算为指导，首次报道了一种新型碳质石墨氮化碳 （g-CN） 催化剂，可促进 Na2S 中间体在 SIBs 中转化为原始 MoS2 的动力学。值得注意的是，g-CN 催化剂的大化学吸附能、高选择性和低催化能势垒可以确保其丰富的电荷转移到 Na2S 中间体，Na2S 中间体化学锚定并分解 Na2S 中间体以催化其可逆转化。此外，微流控策略的开发是为了增强 g-CN 催化剂前驱体在 MoS2 骨架中的质量扩散，以促进它们随后的共价键合过程。g-CN 催化剂在 1T-MoS2 （1T-MoS2/g-CN） 超晶格上的共价键合，通过 C-Mo 键具有很强的界面相互作用，可以极大地促进 MoS2 在放电过程中的 Na+ 储存动力学，并在随后的充电过程中将 Na2S 中间体可逆地转化为原始 MoS2，DFT 计算和原位表征进一步证明了这一点。因此，1T-MoS2/g-CN 超晶格显示出优异的倍率容量和优异的循环稳定性。