Ionic liquid assisted electrochemical coating zinc nanoparticles on carbon cloth as lithium dendrite suppressing host

Li-Ca Alloy Composite Anode with Ant-Nest-Like Lithiophilic Channels in Carbon Cloth Enabling High-Performance Li Metal Batteries

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.

A stable liquid-solid interface of a lithium metal anode enabled by micro-region meshing

Although lithium metal is regarded as the most promising anode for high energy density lithium ion batteries, the unstable solid-liquid interface during cycling severely shortens the battery lifetime. The Li deposition behavior is greatly influenced by the current density distribution on the surface of the electrode, which is significantly associated with the electrode structure. A well-designed electrode structure plays a key role in stabilizing the solid-liquid interface of the Li metal anode. In this work, a lithiophilic honeycomb-like Ni₃N nanosheet array modified Ni foam (Ni₃N@NF) is prepared to stabilize the lithium metal anode. The honeycomb-like Ni₃N nanosheet arrays divide the surface of Ni foam into numerous micro-regions, enabling Li to independently deposit in each mesh. Besides, Li₃N is generated resulting from the in situ reaction between Li and Ni₃N, improving the transportation of Li-ions. Consequently, a symmetrical cell of Ni₃N@NF-Li||Ni₃N@NF-Li achieves stable Li plating/stripping behavior for over 1500 h at a current density of 1 mA cm^-2. Besides, a full cell of Ni₃N@NF-Li||LiFePO₄ exhibits enhanced cycling stability and outstanding rate performance.

Construction of N, P doped 3D dendritic-free lithium metal anode by using silicon-containing lithium metal

Lithium is thought to be an excellent anode material for next-generation Li metal batteries (LMBs). However, some problems with lithium anode often lead to serious safety concerns and catastrophic failures...

Regulating Li nucleation/growth via implanting lithiophilic seeds onto flexible scaffolds enables highly stable Li metal anode

Lithium (Li) metal is deemed as an ideal and promising star anode for high energy storage but its application still is impeded due to uncontrollable Li dendrite growth and tremendous dimension change. Although the flexible and conductive three-dimensional (3D) skeleton can improve the structural and interfacial stability of Li anode, its inherently lithiophobic feature usually brings a high nucleation barrier, uneven Li⁺ flux, and large concentration polarization, leading to inhomogeneous Li plating/stripping. Here, we develop target material (denoted as Mo₂C NPs@CC) consisting of well-distributed molybdenum carbide nanoparticles (Mo₂C NPs) with intrinsic lithiophilicity serving as lithiophilic seeds implanted onto the carbon cloth, breaking the dilemma of ordinary 3D conductive skeletons. The Mo₂C NPs with large Li absorption energy provide plentiful lithiophilic sites for guiding the uniform and thin Li-nuclei layer formation, thereby realizing flat Li growth and stable electrode/electrolyte interface. Moreover, the high electronic conductivity of Mo₂C-modified 3D scaffolds can balance the lithiophilicity, ensuring the fast electron transport in the whole electrode, effectively lowering the local current density, and providing enough space for buffering volume change, and synergistically suppresses the growth of Li dendrites. As a result, a prolonged lifespan of 5000 cycles with low voltage hysteresis of 10 mV at current density of 2 mA cm^-2 with area capacity (C_a) of 1 mA h cm^-2 has been achieved, giving rational guidance for designing high-performance composite Li anodes.

Electrolytes enriched by potassium perfluorinated sulfonates for lithium metal batteries

Lithium (Li) metal is widely considered as a promising anode for next-generation lithium metal batteries (LMBs) due to its high theoretical capacity and lowest electrochemical potential. However, the uncontrollable formation of Li dendrites has prevented its practical application. Herein, we propose a kind of multi-functional electrolyte additives (potassium perfluorinated sulfonates) from the multi-factor principle for electrolyte additive molecular design (EDMD) view to suppress the Li dendrite growth. The effects of these additives are revealed through experimental results, molecular dynamics simulations and first-principles calculations. Firstly, K⁺ can form an electrostatic shield on the surface of Li anode to prevent the growth of Li dendrites. Secondly, potassium perfluorinated sulfonates can improve the activity of electrolytes as co-conductive salts, and lower the electro-potential of Li nucleation. Thirdly, perfluorinated sulfonate anions not only can change the Li⁺ solvation sheath structure to decrease the desolvation energy barrier and increase the ion migration rate, but also can be partly decomposed to form the superior solid electrolyte interphase (SEI). Benefited from the synergistic effects, an outstanding cycle life over 250 h at 1 mA cm^-2 is achieved in symmetric Li||Li cells. In particular, potassium perfluorinated sulfonate additives (e.g., potassium perfluorohexyl sulfonate, denoted as K⁺PFHS) can also contribute to the formation of high-quality cathode electrolyte interphase (CEI). As a result, Li||LiNi_0.6Mn_0.2Co_0.2O₂ full cells exhibit significantly enhanced cycling stability. This multi-factor principle for EDMD offers a unique insight on understanding the electrochemical behavior of ion-type electrolyte additives on both the Li metal anode and high-voltage cathode.