Lithium-sulfur batteries are regarded as promising next-generation energy storage batteries for their ultra-high theoretical energy density. However, the complex sulfur electrode process with sluggish sulfur conversion reactions is a critical issue for lithium-sulfur batteries, in which catalytic interfacial reactions and accelerated lithium-ion diffusion are the key factors. Our previous work has shown that implanting functional molecules with multiple redox properties in the electrode can break through the conventional diffusion layer constraints and achieve forced convection. In this work, a functionalized complex molecule, methylene blue anthraquinone-2-sulfonate (MB-AQ), with multiple redox activities as well as abundant active sites, was synthesized and introduced into the sulfur cathode. In addition to accelerating the transport of lithium ions by reversible inhaling and exhaling lithium ions, the MB-AQ can combine polysulfides by its active sites to accelerate sulfur conversion reactions. Benefiting from two functions of accelerating ion diffusion and catalyzing interfacial reactions, MB-AQ/reduced graphene oxide (rGO)/S cathode can achieve high initial capacities of 884 and 674 mAh·g⁻¹ with stable cycling of 700 and 1,000 times at 1 and4 C, respectively. It is worth mentioning that the capacity of 462 mAh·g⁻¹ can be achieved even at a high current density of 6 C. This work provides a new approach to enhancing the sulfur cathode process.

The metallic Na has been regarded as the most promising anode for next-generation sodium metal batteries (SMBs) owing to its high theoretical specific capacity, low redox potential, and low cost. The practical applications of Na metal, however, have still been severely hindered by the uncontrolled sodium dendrites growth during Na deposition and stripping processes, which leads to low Coulombic efficiency and poor cycling stability. In this study, sub-nano zinc oxide (ZnO) uniformly dispersed in three-dimensional (3D) porous nitrogen-doped (N-doped) carbon nanocube (ZnO@NC) was acquired as a stable host for dendrite-free Na metal anode. Benefiting from the in-situ electrochemically formed sodiophilic nucleation site (NaZn₁₃ alloy) and the enriched pore structure, rapid and uniform sodium deposition behavior can be performed. As expected, the ZnO@NC electrode delivers impressive electrochemical performance, an ultra-high areal capacity of 20 mAh·cm⁻² in the half-cell can be maintained for 2,000 h. In the symmetrical-cell, it can also exhibit up to 3,000 h at 3 mA·cm⁻² and 3 mAh·cm⁻² with low polarization potential. Furthermore, in the full-cell that matches with Prussian blue (PB) cathode, the Na@ZnO@NC anode performs the outstanding long-cycling and rate performance. Therefore, this work provides an effective strategy to inhibit the growth of Na dendrites for the development of high-safety and long-cycling SMBs.

The high-voltage battery has now become a goal in order to meet the demands for high energy density. However, the severe side reactions between Li metal and carbonate-based electrolytes in this system result in unstable interphase, leading to non-uniform Li-ion flux and thus aggravating the dendrite growth of Li. The protect interphase, traditional solid electrolyte interface (SEI), is a loose solid layer consisted of many components, which generally does not possess the function of preventing the lithium budding. Herein, based on polysulfide solubility in ester, we proposed a strategy to eliminate the dendrite by constructing a unique SEI in which the dynamic polysulfides were in situ formed and encapsuled. For this purpose, a 2-fluorophenylsulfur pentafluoride (2-FSPF) was employed as an additive in carbonate-based electrolyte that can be decomposed electrochemically during battery operation to form such a polysulfide-rich interphase. These polysulfides with certain fluidity can adhere to dynamically the budding tip of Li metal, as a so-called tip-inhibitor, when the local current density of the tip rising, thus to hinder Li⁺ diffusion toward the tip, resulting in inhibiting the further growth of Li dendrites and leveling the Li deposition. At the current density of 1 mA cm⁻², the average Coulombic efficiency of Li//Cu cells is as high as 98.39% during 600 cycles, and the stable cycling of Li//Li symmetric cell reaches 3500 h. Furthermore, due to the high anodic stability, the Li//high-voltage LiCoO₂ (LCO) full cells and Li–O₂ battery achieve excellent cycle performance with lean electrolyte.