Lithium metal anodes are ideal for realizing high-energy-density batteries owing to their advantages, namely high capacity and low reduction potentials. However, the utilization of lithium anodes is restricted by the detrimental lithium dendrite formation, repeated formation and fracturing of the solid electrolyte interphase (SEI), and large volume expansion, resulting in severe “dead lithium” and subsequent short circuiting. Currently, the researches are principally focused on inhibition of dendrite formation toward extending and maintaining battery lifespans. Herein, we summarize the strategies employed in interfacial engineering and current-collector host designs as well as the emerging electrochemical catalytic methods for evolving-accelerating-ameliorating lithium ion/atom diffusion processes. First, strategies based on the fabrication of robust SEIs are reviewed from the aspects of compositional constituents including inorganic, organic, and hybrid SEI layers derived from electrolyte additives or artificial pretreatments. Second, the summary and discussion are presented for metallic and carbon-based three-dimensional current collectors serving as lithium hosts, including their functionality in decreasing local deposition current density and the effect of introducing lithiophilic sites. Third, we assess the recent advances in exploring alloy compounds and atomic metal catalysts to accelerate the lateral lithium ion/atom diffusion kinetics to average the spatial lithium distribution for smooth plating. Finally, the opportunities and challenges of metallic lithium anodes are presented, providing insights into the modulation of diffusion kinetics toward achieving dendrite-free lithium metal batteries.

Lithium–sulfur (Li–S) batteries exhibit unparalleled theoretical capacity and energy density than conventional lithium ion batteries, but they are hindered by the dissatisfactory “shuttle effect” and the sluggish conversion kinetics owing to the low lithium ion transport kinetics, resulting in rapid capacity fading. Herein, a catalytic two-dimensional heterostructure composite is prepared by evenly grafting mesoporous carbon on the MXene nanosheet (denoted as OMC-g-MXene), serving as interfacial kinetic accelerators in Li–S batteries. In this design, the grafted mesoporous carbon in the heterostructure can not only prevent the stack of MXene nanosheets with the enhanced mechanical property but also offer a facilitated pump for accelerating ion diffusion. Meanwhile, the exposed defect-rich OMC-g-MXene heterostructure inhibits the polysulfide shuttling with chemical interactions between OMC-g-MXene and polysulfides and thus simultaneously enhances the electrochemical conversion kinetics and efficiency, as fully investigated by in situ/ex situ characterizations. Consequently, the cells with OMC-g-MXene ion pumps achieve a high cycling capacity (966 mAh g–1 at 0.2 C after 200 cycles), a superior rate performance (537 mAh g–1 at 5 C), and an ultralow decaying rate of 0.047% per cycle after 800 cycles at 1 C. Even employed with a high sulfur loading of 7.08 mg cm–2 under lean electrolyte, an ultrahigh areal capacity of 4.5 mAh cm–2 is acquired, demonstrating a future practical application.

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