All‐Solid‐State Batteries with a Limited Lithium Metal Anode at Room Temperature using a Garnet‐Based Electrolyte

Abstract

energy density, and cost effective. Albertus et al. have advocated for the use of limited lithium (≤30 µm) to ensure early identification of technical challenges associated with stable and dendrite-free cycling and a more rapid transition to commercially relevant designs. [7] And recently, Liu et al. [8] re-emphasized the importance of limited lithium and announced that 50 µm Li anode was required to reach a high energy of 300 Wh kg −1. Therefore, for practical lithium-metal batteries (LMBs), the utilization of thin Li metal anode with thicknesses <30 µm (<6 mAh cm −2) is extremely necessary. [6-10] In other words, the negative to positive electrode capacity ratio (N/P ratio) must be strictly restricted. Limiting the amount of Li metal anode is a great challenge, since it is highly reactive. The continuous reaction of Li metal with electrolyte to generate a solid electrolyte interphase (SEI) as well as the uneven Li platting to form dendrite growth and pulverized Li metal, which cause fast consumptions of Li metal and electrolyte, low Coulombic efficiency (CE), and short lifespan of LMBs. To improve cycling stability of Li metal anode in organic liquid electrolyte, various attempts have already been made, including highly concentrated electrolyte, [11] electrolyte additives, [12,13] external pressure, [14,15] Li host, [16,17] and surface coating. [18,19] While most of the above strategies use unlimited Li foil, only a few studies focus on limiting the amount of Li metal for LMBs. [6,9,20,21] For example, Niu et al. reported a self-smoothing Li-carbon anode based on the host of mesoporous carbon nanofibers and a high-energy LMB with a low N/P ratio of ≤2. [6] Archer's group and Cho's group achieved stable operations of LMBs composed of a high-loading cathode and a thin Li anode (20 µm) with Langmuir-Blodgett artificial SEIs. [9] While, compared with liquid electrolyte, some types of solid electrolytes are less reactive with Li metal, which may be good candidates for LMBs with low N/P ratios. [22] Additionally, the safety of LMBs can be greatly improved by replacing flammable liquid electrolyte with solid electrolyte. [23] But, up to now, there are only a few researches about all-solidstate lithium-metal batteries (ASSLMBs) using limited amount of Li metal anode. A recent work reported an ASSLMB with Li 6 PSCl sulfide electrolyte and Ag-C composite anode with no excess Li. [24] Besides, the studies of LiPON-based thin-film batteries with limited Li metal have been reported, which are Metallic lithium (Li), considered as the ultimate anode, is expected to promise high-energy rechargeable batteries. However, owing to the continuous Li consumption during the repeated Li plating/stripping cycling, excess amount of the Li metal anode is commonly utilized in lithium-metal batteries (LMBs), leading to reduced energy density and increased cost. Here, an all-solid-state lithium-metal battery (ASSLMB) based on a garnet-oxide solid electrolyte with an ultralow negative/positive electrode capacity ratio (N/P ratio) is reported...

Ultrathin Layered Double Hydroxide Nanosheets Enabling Composite Polymer Electrolyte for All‐Solid‐State Lithium Batteries at Room Temperature

“…[ 13 ] Also, oxides such as garnet‐typed Li 7 La 3 Zr 2 O 12 (LLZO) and their derivates also demonstrate decent ionic conductivity, wide electrochemcial window, and excellent chemical stability against Li metal, which have been widely investigated for solid‐state lithium metal batteries. [ 14–17 ] However, the brittleness, poor air stability, and the relatively poor electrode/electrolyte interfacial contact severely fettered the usage of inorganic solid electrolyte and facile, commercially competitive, and scalable preparation technologies are also imperatively to be developed. Comparatively, solid polymer electrolytes reveal the superiorities in terms of excellent flexibility, light weight, and easy‐preparation, which thus deliver a promising prospect for scalable usage especially in powering the flexible electronics.…”

Toward High Performance All‐Solid‐State Lithium Batteries with High‐Voltage Cathode Materials: Design Strategies for Solid Electrolytes, Cathode Interfaces, and Composite Electrodes

“…Second, a thick composite cathode with a sufficiently high active material (AM) proportion is desirable for high-voltage ASSLBs to achieve higher energy density. [10] Third, the structures and compositions of the composite cathodes should be well designed to ensure stable internal interfaces and efficient Li + as well as electron conductive pathways. [11] As next-generation batteries, high-voltage ASSLBs possess great potential, but advancing their development and practical application remains difficult owing to the limitations from SEs and battery internal interfaces.…”

Enabling High‐Performance NASICON‐Based Solid‐State Lithium Metal Batteries Towards Practical Conditions

“…Moreover, most of the literature work used thick Li metal (>0.5 mm) to pair with thin cathodes. [9][10][11]13,15,17,20,21] Both of them will dramatically decrease the practical energy density of SSLMBs. Table 1, Figure 1c,d summarize the cell parameters of the reported SSLMBs using oxide-based SSEs, which clearly show that an SSLMB configuration based on thin oxide SSE, thin Li metal, and thick cathode (Figure 1b) to enable high practical energy density has yet to be reported.…”