Constructing a three-dimensional (3D) multifunctional hosting architecture and subsequent thermal infusion of molten Li to produce advanced Li composite is an effective strategy for stable Li metal anode. However, the pure liquid Li is difficult to spread across the surface of various substrates due to its large surface tension and poor wettability, hindering the production and application of Li composite anode. Herein, heteroatomic Ca is doped into molten Li to generate Li-Ca alloy, which greatly regulates the surface tension of the molten alloy and improves the wettability against carbon cloth (CC). Moreover, a secondary network composed of CaLi2 intermetallic compound with interconnected ant-nest-like lithiophilic channels is in situ formed and across the primary scaffold of CC matrix by infiltrating molten Li-Ca alloy into CC and then cooling treatment (LCAC), which has a larger and lithiophilic surface to enable uniform Li deposition into interior space of the hybrid scaffold without Li dendrites. Therefore, LCAC exhibits a long-term lifespan for 1100 h under a current density of 5 mA cm-2 with fixed areal capacity of 5 mAh cm-2. Remarkably, full cells paired with practical-level LiFePO4 cathode of 2.45 mAh cm-2 deliver superior performance.
To develop high‐performance lithium‐sulfur (Li−S) batteries, designing and exploring an advanced sulfur cathode with a conductive and polar robust framework is highly significant to suppress the “shuttle effect” of polysulfides and enhance the utilization of active sulfur. Herein, a multifunctional conductive nanohybrid, which acts as a sulfur host, is rationally constructed by inserting/intertwining carbon nanotubes (CNTs) onto Co‐embedded N‐doped porous dual carbon polyhedrons derived from a resorcinol‐formaldehyde (RF) polymer layer enwrapping ZIF‐67 metal‐organic frameworks (MOFs) (Co, N−C@RFC/CNTs). The porous carbon polyhedrons can accommodate a high amount of sulfur owing to their large inner void space; the RF coating carbon layer and the CNTs effectively increase the conductivity and build a network for providing smooth ions/e− pathways; In addition, the polar Co particles and electronegative N heteroatoms synergistically strengthen the chemical adsorption of polysulfides and accelerate the redox reaction of the sulfur cathode. Benefiting from these advantages, the as‐fabricated Co, N−C@RFC/CNTs/S cathode delivers a high reversible capacity of 1373.7 mAh g−1 at 0.1 C, an impressive rate performance with 659.2 mAh g−1 at 2.0 C, and an outstanding cycling stability with an ultralow capacity decay rate of 0.041 % per cycle for 500 cycles at 1.0 C. This work provides a facile and high‐efficiency approach to fabricating excellent‐performance storage materials based on an MOF precursor.
High-voltage LiNi0.5Mn1.5O4 is a promising cathode candidate for lithium-ion batteries (LIBs) due to its considerable energy density and power density, but the material generally undergoes serious capacity fading caused by side reactions between the active material and organic electrolyte. In this work, Li+-conductive Li2SnO3 was coated on the surface of LiNi0.5Mn1.5O4 to protect the cathode against the attack of HF, mitigate the dissolution of Mn ions during cycling and improve the Li+ diffusion coefficient of the materials. Remarkable improvement in cycling stability and rate performance has been achieved in Li2SnO3-coated LiNi0.5Mn1.5O4. The 1.0 wt% Li2SnO3-coated LiNi0.5Mn1.5O4 cathode exhibits excellent cycling stability with a capacity retention of 88.2% after 150 cycles at 0.1 C and rate capability at high discharge rates of 5 C and 10 C, presenting discharge capacities of 119.5 and 112.2 mAh g-1, respectively. In particular, a significant improvement in cycling stability at 55 °C is obtained after the coating of 1.0 wt% Li2SnO3, giving a capacity retention of 86.8% after 150 cycles at 1 C and 55 °C. The present study provides a significant insight into the effective protection of Li-conductive coating materials for a high-voltage LiNi0.5Mn1.5O4 cathode material.
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