Advanced Porous Carbon Materials for High‐Efficient Lithium Metal Anodes

Abstract

choices for the next-generation energy storage devices because of their surpassed energy output. [3] However, the inherent defects of Li anode incur serious problems that restrict the utilization of rechargeable Li metal batteries. [4] First, an uneven plating/stripping of Li leads to the formation and growth of Li dendrites. The formed Li dendrites may puncture the separator and induce internal short circuit, bring severe safety concerns. Second, Li has a relatively high Fermi energy and thus easily reacts with the liquid electrolyte to form an unstable solid-electrolyte interphase (SEI) on the anode surface. The persistent reaction between Li metal and electrolyte consumes both of them, and results in a low Coulombic efficiency and rapid capacity fade of anode. Third, the plating of Li is actually a "hostless" process. Therefore, the relative change of volume for Li metal anode is virtually infinite, which may induce immense internal stress fluctuation of battery and account for seriously deteriorated performance.Great efforts have been devoted to addressing the above problems of Li anode. A number of works focus on optimizing the electrolyte components and additives to homogenize the Li + flux for plating and improve the stability and uniformity of the SEI on the anode surface. [5] However, the resultant SEI layer has been revealed not sufficiently sturdy to accommodate the morphological change of the Li anode surface, and can be broken down upon repeated Li plating/stripping. [6] Therefore, solid electrolytes and various mechanical barriers with high shear modulus have been explored to suppress dendrite formation. [7] Given the simple physical blocking function of the mechanical barrier, these strategies do not alter the fundamental chemical/ electrochemical properties of Li and thereby show a limited dendrite-proof effect. Furthermore, most solid electrolytes show low ionic conductivity and critical interfacial issues in their contacts with both electrodes. Recently, the development of a threedimensional (3D) porous current collector has been considered as a feasible route to prohibit the growth of Li dendrite. [8] The 3D interconnected architectures provide a large specific surface area, enabling low current density and uniform distribution of the positive charges, while the porous structure ensures ample space to accommodate Li, limiting the growth of Li dendrite and alleviating the huge volume change of Li metal during cycling. For example, 3D porous copper current collector consisting of a large number of protuberant tips has been regarded Metallic lithium is considered as a competitive anode candidate for rechargeable Li batteries due to its ultrahigh theoretical specific capacity of 3860 mA h g −1 . However, hurdles regarding the uneven Li deposition, unstable solid electrolyte interphase formation, and infinite change of relative dimensions challenge its practical application. Porous carbons (PCs), due to their high conductivity and stable electrochemistry, have been demonstrated feasible as ho...

Constructing a High‐Strength Solid Electrolyte Layer by In Vivo Alloying with Aluminum for an Ultrahigh‐Rate Lithium Metal Anode

“…For example, an increased concentration of lithium bis(fluorosulfonyl)imide salt (LiFSI) in 1,2‐dimethoxyethane (DME) resulted in the growth of a LiF‐rich SEI and improved Li anode stability at 10 mA cm −2 , and Xia and co‐workers improved the Li anode stability (100 cycles at 10 mA cm −2 ) by constructing a LiF and Li 3 N‐rich artificial SEI . The latter strategy is often effective at current densities less than 10 mA cm −2 because the low mechanical strength of the SEI produced from conventional electrolyte decomposition is unable to withstand large volume changes during Li stripping and plating ( Figure ) . Further improvements to the high rate performance of a Li metal battery at current densities of 20 mA cm −2 by simply modifying the composition and strength of the SEI are highly desirable but challenging.…”

Review—Li Metal Anode in Working Lithium-Sulfur Batteries

“…172 These matrixes can regulate the nucleation and growth of Li ion by the lithiophilic sites and suppress Li dendrite growth by the increased surface areas. 173,174 The conventional Li−S batteries take elemental S as the cathode, while Li is stored in the anode. These above-mentioned hosts are merely matrixs without Li in them and most of conceptual advance- Even at 10.0 mA cm −2 , no Li dendrite is observed, enabling a 2000-cycle long lifespan in Li−S batteries with a Coulombic efficiency higher than 90%.…”

Stable Li Metal Anode Enabled by Space Confinement and Uniform Curvature through Lithiophilic Nanotube Arrays

“…[16,17] Recently, hosting Li metal inside a 3D scaffold has been found to be one of the most effective approaches to solve this challenge. [18][19][20] A high specific surface area of the 3D scaffold decreases the effective current density and thus delays the Li dendrite formation, in accordance with Sand's formula. [21] In addition, the 3D structure provides confined space to accommodate Li plating, mitigating massive volume changes.…”