Search

Li metal is regarded as the "Holy Grail" in the next generation of anode materials due to its high theoretical capacity and low redox potential. However, sluggish Li ions interfacial transport kinetics and uncontrollable Li dendrites growth limit practical application of the energy storage system in high‐power device. Herein, separators are modified by the addition of a coating, which spontaneously grafts onto the Li anode interface for in situ lithiation. The resultant alloy possessing of strong electron‐donating property promotes the decomposition of lithium bistrifluoromethane sulfonimide in the electrolyte to form a LiF‐rich alloy‐doped solid electrolyte interface (SEI) layer. High ionic alloy solid solution diffusivity and electric field dispersion modulation accelerate Li ions transport and uniform stripping/plating, resulting in a high‐power dendrite‐free Li metal anode interface. Surprisingly, the formulated SEI layer achieves an ultra‐long cycle life of over 8000 h (20,000 cycles) for symmetric cells at a current density of 10 mA cm−2. It also ensures that the NCM(811)//PP@Au//Li full cell at ultra‐high currents (40 C) completes the charging/discharging process in only 68 s to provide high capacity of 151 mAh g−1. The results confirm that this scalable strategy has great development potential in realizing high power dendrite‐free Li metal anode. [ABSTRACT FROM AUTHOR]

Despite lithium‐sulfur (Li‐S) batteries possessing ultrahigh energy density as great promising energy storage devices, the suppressing shuttle effect and improving sulfur redox reaction (SROR) are vital for their practical application. Developing high‐activity electrocatalysts for enhancing the SROR kinetics is a major challenge for the application of Li‐S batteries. Herein, single‐molecule iron phthalocyanine species are anchored on the N and P dual‐doped porous carbon nanosheets (Fe‐NPPC) via axial Fe‐N coordination to optimize the electronic structure of active centers. The Fe‐NPPC can promote the catalytic conversion of polysulfides by modulation of the electronic density in active moieties, endowing the Li‐S battery with a high reversible capacity of 1023 mAh g−1 at 1 C as well as an ultralow capacity decay of 0.035% per cycle over 1500 cycles. Even with a high sulfur loading of 7.1 mg cm−2, the Li‐S battery delivers a high areal capacity of 4.8 mAh cm−2 after 150 cycles at 0.2 C. With further increasing the sulfur loading to 9.2 mg cm−2, an excellent areal capacity of up to 9.3 mAh cm−2 is obtained at 0.1 C. [ABSTRACT FROM AUTHOR]

Li metal with high‐energy density is considered as the most promising anode for the next‐generation rechargeable Li metal batteries; however, the growth of Li dendrites seriously hinders its practical application. Herein, 3D free‐standing carbon nanofibers modified by lithiophilic metal particles (CNF/Me, Me=Sn, Fe, Co) are obtained in situ by the electrospinning method. Benefiting from the lithophilicity, the CNF/Me composite may effectively prevent the formation of Li dendrites in the Li metal batteries. The optimized CNF/Sn–Li composite electrode exhibits a stable cycle life of over 2350 h during Li plating/stripping. When matched with typical commercial LiFePO4 (LFP) cathode, the LFP//CNF/Sn–Li full cell presents a high initial discharge specific capacity of 139 mAh g−1 at 1 C, which remains at 146 mAh g−1 after 400 cycles. When another state‐of‐the‐art commercial LiNi0.8Co0.1Mn0.1O2 (NCM(811)) cathode is used, the assembled NCM//CNF/Sn–Li full cell shows a large initial specific discharge capacity of 206 mAh g−1 at substantially enhanced 10 C, which keeps at the good capacity of 99 mAh g−1 after 300 cycles. These results are greatly superior to the counterparts with Li as the anodes, indicating the great potential for practical utilization of the advanced CNF/Sn–Li electrode. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries show great promise to serve as high-energy-density energy storage devices. Nevertheless, the practical applications of Li–S batteries are significantly limited by the shuttle effect and sluggish sulfur redox reaction (SROR) kinetics. Herein, an ingenious urea-mediated pyrolysis strategy is for the first time reported to obtain well-defined atomically distributed asymmetrical five-coordinated Co–N5 moieties anchored on nitrogen-rich (30.0 at%) doped carbon (CoN5 SA/NC) as a highly efficient SROR electrocatalyst. CoN5 SA/NC with a high atomically distributed Co loading (2.12 wt%) effectively catalyzes the liquid–liquid and liquid–solid conversions of lithium polysulfides greatly accelerating the SROR kinetics. When CoN5 SA/NC is served as a coating layer for the separator, the Li–S battery exhibits outstanding capacity properties (1060 mA h g−1 at 1C and 922 mA h g−1 at 2C) and superior cycling stability (ultralow decay of 0.033% per cycle at 3C for 1600 cycles). An ultrahigh areal capacity of 7.25 mA h cm−2 can be acquired for the CoN5 SA/NC based Li–S battery even with a high sulfur loading of 6.5 mg cm−2. Obviously, the asymmetrical single-atom site engineering strategy demonstrates great potential for practical applications of advanced metal–S batteries. [ABSTRACT FROM AUTHOR]

Li metal is considered to be one of the most superior battery anode materials in high energy storage devices. However, Li dendrite generation and infinite dimensional change during long-term cycling limit its practical applications. To solve these problems, we design a thermal infusion strategy to prepare a Li–LiAl alloy composite based on the strong bonding force between Al and liquid Li. Compared with bare Li, Li–LiAl electrode exhibits a stable voltage profile and maintains an extremely low overpotential of 15 mV after 550 cycles at 1 mA cm−2. When Li 4 Ti 5 O 12 or LiFePO 4 are used as the counter electrodes to assemble full cells, the batteries show high capacities and stable cycling performance. Through scanning electron microscope image observation, it is found that Li–Al 3D skeleton could be formed when Li is stripped. During Li planting process, Li returns in the skeleton structure, and no Li dendrites formed on the surface of the electrode, indicating the memory effect of Li migration. It is possible that Li and Li–Al alloy have strong affinity and tend to re-deposit on the surface of Li–Al alloy. This kind of structure plays an important role in maintaining stability and improving the electrochemical performance of the Li–Al composite. Image 1 • A novel Li–LiAl alloy composite was prepared by a thermal infusion method. • It exhibited a stable voltage profile and maintained an extremely low overpotential. • Li can be freely stripping/planting in 3D Li–Al skeleton. • Li–LiAl electrode can effectively avoid the formation of Li dendrites on the surface. • This memory effect based on the strong affinity between Li and LiAl alloy. [ABSTRACT FROM AUTHOR]