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Adv Mater ; 32(2): e1905517, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31782563


Solid-state lithium-metal batteries with solid electrolytes are promising for next-generation energy-storage devices. However, it remains challenging to develop solid electrolytes that are both mechanically robust and strong against external mechanical load, due to the brittleness of ceramic electrolytes and the softness of polymer electrolytes. Herein, a nacre-inspired design of ceramic/polymer solid composite electrolytes with a "brick-and-mortar" microstructure is proposed. The nacre-like ceramic/polymer electrolyte (NCPE) simultaneously possesses a much higher fracture strain (1.1%) than pure ceramic electrolytes (0.13%) and a much larger ultimate flexural modulus (7.8 GPa) than pure polymer electrolytes (20 MPa). The electrochemical performance of NCPE is also much better than pure ceramic or polymer electrolytes, especially under mechanical load. A 5 × 5 cm2 pouch cell with LAGP/poly(ether-acrylate) NCPE exhibits stable cycling with a capacity retention of 95.6% over 100 cycles at room temperature, even undergoes a large point load of 10 N. In contrast, cells based on pure ceramic and pure polymer electrolyte show poor cycle life. The NCPE provides a new design for solid composite electrolyte and opens up new possibilities for future solid-state lithium-metal batteries and structural energy storage.

ACS Appl Mater Interfaces ; 11(32): 28774-28780, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31314493


Safety is critical to developing next-generation batteries with high-energy density. Polyether-based electrolytes, such as poly(ethylene oxide) and poly(ethylene glycol) (PEG), are attractive alternatives to the current flammable liquid organic electrolyte, since they are much more thermally stable and compatible with high-capacity lithium anode. Unfortunately, they are not stable with 4 V Li(NixMnyCo1-x-y)O2 (NMC) cathodes, hindering them from application in batteries with high-energy density. Here, we report that the compatibility between PEG electrolyte and NMC cathodes can be significantly improved by forming a 2 nm Al2O3 coating on the NMC surface. This nanoscale coating dramatically changes the composition of the cathode electrolyte interphase and thus stabilizes the PEG electrolyte with the NMC cathode. With Al2O3, the capacity remains at 84.7% after 80 cycles and 70.3% after 180 cycles. In contrast, the capacity fades to less than 50% after only 20 cycles in bare NMC electrodes. This study opens a new opportunity to develop safe electrolyte for lithium batteries with high-energy density.