Three-Dimensional Porous Frameworks for Li Metal Batteries: Superconformal versus Conformal Li Growth

Abstract

Li metal batteries have been considered a promising alternative to Li-ion batteries because of the high theoretical capacity of the Li metal. There have been remarkable improvements in the electrochemical performance of Li metal electrodes, although the current Li metal technology is not sufficiently practical in terms of cycle performance, safety, and volume change during cycling. Herein, the role of pore size distribution in the Li metal plating behavior of porous frameworks is clarified to attain the ideal pore structure of the framework as a Li metal host. The monodisperse pore framework shows the conformal electrodeposition of the Li metal, whereas the pore size gradient framework exhibits the superconformal plating of the Li metal. The conformal and superconformal electrodepositions of the Li metal are elucidated in terms of variations along the pore depth direction in the charge-transfer resistance on the pore walls and the ionic resistance of electrolytes confined in pores. The pore size gradient framework also shows excellent electrochemical performance, such as stable capacity retention over 760 cycles with 0.5 mAh cm–2 at 2 mA cm–2. These findings provide fundamental insights into strategies to improve the electrochemical performance of porous frameworks for Li metal batteries.

Designing a Bimodal BaTiO3 Artificial Layer to Boost the Dielectric Effect toward Highly Reversible Dendrite-Free Zn Metal Anodes

“…In this situation, the charge is uniformly distributed at the interface, which can affect the redox process in the battery and ultimately limit the Zn dendrite formation and growth, enabling reversible Zn plating/stripping. , In addition, the porosity of the artificial interface layer can facilitate effective mechanical transformation and homogenization of the Zn ion flux. In addition, it can mechanically accommodate the volume changes of the Zn anode during the repetitive charge/discharge processes, contributing to a long cycle life …”

“…In addition, it can mechanically accommodate the volume changes of the Zn anode during the repetitive charge/discharge processes, contributing to a long cycle life. 32 In this study, a BaTiO 3 (BTO) artificial layer with bimodal particles was used to improve the stabilization of the Zn-metal anode (Figure 1). The BTO layer on the Zn anode can induce a polarized electric field on the surface or switch the polarization under an external electric field because the ionically bonded Ti 4+ deviates from the center of the octahedral [TiO 6 ] cluster under the applied electric field.…”

Achieving Electronic Engineering of Vanadium Oxide-Based 3D Lithiophilic Sandwiched-Aerogel Framework for Ultrastable Lithium Metal Batteries

“…Lithium metal has received growing attention for next-generation energy devices due to its lightweight of 0.534 g cm −3 , high theoretical capacity of 3860 mAh g −1 , and low redox potential (−3.04 V vs the standard hydrogen electrode). − However, the practical application of lithium metal anode is greatly impeded by the tendency of lithium dendrites formation. − The durative growth of the dendrites could induce severe side reactions, leading to excessive electrolyte consumption and unstable SEI film and thus short cycle life. − Additionally, dead lithium will be formed when the dendrites continue to grow, and then separate from the electrode, which could bring serious safety hazards. − Hence, many strategies have been employed to prohibit the formation of dendrites, such as the employment of electrolyte additives, − the design of high modulus solid/composite electrolytes, − and the use of stable artificial interface. ,− Although these strategies have made great progress in the past decades, it is still challenging to construct a host that can effectively inhibit the dendrite growth. In generally, a desired Li host for composite anode construction is expected to meet the two requirements: (1) sufficient room to accommodate Li metal, , and (2) interconnected and excellent conductive network for electron-transporting .…”

3D Carbon-Based Porous Anode with a Pore-Size Gradient for High-Performance Lithium Metal Batteries

“…Consequently, 3D-CPA was synthesized with a pore size gradient in the current study, with the upper layer of the electrode having a large pore to inhibit Li deposition on the top surface layer and the bottom layer having smaller pores for guiding the stable Li deposition/dissolution reaction. This multi-layered porous electrode with varying pore sizes may facilitate Li-ion transport and reduce the possibility of inhomogeneous Li plating, resulting in outstanding cycling performances . Additionally, we fabricated a full cell using LiNi 0.6 Co 0.2 Mn 0.2 (NCM622) with a cathode capacity of 4 mA h cm –2 and 3D-CPA with a pore size gradient (NP ratio = 2:1) to evaluate the level of energy density required for commercial usage.…”

“…This multi-layered porous electrode with varying pore sizes may facilitate Li-ion transport and reduce the possibility of inhomogeneous Li plating, resulting in outstanding cycling performances. 37 Additionally, we fabricated a full cell using LiNi 0.6 Co 0.2 Mn 0.2 (NCM622) with a cathode capacity of 4 mA h cm −2 and 3D-CPA with a pore size gradient (NP ratio = 2:1) to evaluate the level of energy density required for commercial usage.…”