Asymmetric Structure Design of Electrolytes with Flexibility and Lithium Dendrite-Suppression Ability for Solid-State Lithium Batteries

Abstract

Solid polymer electrolytes can be used to construct solid-state lithium batteries (SSLBs) using lithium metals as the anode. However, the lifespan and safety problems of SSLBs caused by lithium dendrite growth have hindered their practical application. Here, we have designed and prepared a rigid-flexible asymmetric solid electrolyte (ASE) that is used in building SSLBs. The ASE can inhibit efficiently the growth of lithium dendrites and lead to a long cycle life of SSLBs due to the hierarchical structure of a combination of “polymer-in-ceramic” (i.e., rigid ceramic layer of Li6.4La3Zr1.4Ta0.6O12) and “LiBOB-in-polymer” (i.e., soft polymer-layer of polyethylene oxide and LiBOB components). The results demonstrated that a symmetrical battery with ASE (Li|ASE|Li) can be steadily cycled for more than 2000 h and yielded a flat plating/stripping voltage profile under a current density of 0.1 mA cm–2. As a consequence, the SSLB of LiFePO4|ASE|Li delivered a specific capacity of 155.1 mA h g–1 with a capacity retention rate up to 90.2% after 200 cycles with the Coulombic efficiency over 99.6% per cycle. This asymmetric structure combines the advantages of ceramics and polymers, providing an ingenious solution for building rigid and flexible solid electrolytes.

Status and prospect of garnet/polymer solid composite electrolytes for all-solid-state lithium batteries

“…With https://engine.scichina.com/doi/10.1016/j.jechem.2020.03.017 [145] this battery configuration, the NCM622|LLZTO/PPC|Li battery can exhibit good comprehensive electrochemical performances, with an initial discharge capacities of 162.0 and 130.1 mAh g −1 at 1 and 3 C, respectively, and capacity retention of 77.3% after 150 cycles at 3 C under room temperature, although the used LLZTO/PPC SCE shows moderate ionic conductivity of 1.57 × 10 −4 S cm −1 . Similar to the concept of the asymmetric structure design of electrolytes, Sun's groupreported a rigid-flexible asymmetric solid electrolyte (ASE) that was successfully used in building ASSLBs [146] . The ASE efficiently suppresses the growth of lithium dendrites and enables the LiFePO 4 |ASE|Li cell with good cycle performance because of the hierarchical structure of a combination of "polymer-in ceramic" (rigid ceramic layer of Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 , which is close to Li anode) and "LiBOB in-polymer" (soft polymer-layer of polyethylene oxide and LiBOB components, which is close to cathode).…”

Dense PVDF-type polymer-in-ceramic electrolytes for solid state lithium batteries

“…S3b †) with capacities of 136.4, 131.9, 122, 102, and 67.3 mA h g À1 at current rates of 0.1, 0.2, 0.5, 0.8 and 1 C, respectively. Compared with the works reported recently in Table S1, † LPCE-10 shows relatively high ionic conductivity and reversible capacity of the cell at 60 C. [28][29][30][31][32][33] Our work also shows a relatively simple way for cell preparation. 30 These suggest the strategy of SSE preparation shown in this work would be promising for the application of high energy lithium batteries.…”

“…S3a †), which is much lower than that of LLZTO. 30 This should be related to the exibility of LPCE-10 as shown in Fig. 1a.…”

Structural Design of Composite Polymer Electrolytes for Solid‐state Lithium Metal Batteries

“…The obtained CPE effectively reduces the interfacial resistance and exhibits an electrochemical window of 5 V, as well as excellent cycle and rate performance when matched with NCM811 and NCM622 [89] . In conclusion, for designing such sandwich composite electrolyte, the rational selection of materials for each layer with particular function and tightly assemble the electrolyte layers together are essential and needs more exploration in the future [90–101] …”