The development of high-performance solid-polymer electrolytes (SPEs) is a key to the practical application of lithium metal batteries (LMBs). The use of two-dimensional (2D) inorganic nanofiller is an efficient way to build poly(ethylene oxide) (PEO)-based SPEs with high ionic conductivity and stability. Herein,
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The development of high-performance solid-polymer electrolytes (SPEs) is a key to the practical application of lithium metal batteries (LMBs). The use of two-dimensional (2D) inorganic nanofiller is an efficient way to build poly(ethylene oxide) (PEO)-based SPEs with high ionic conductivity and stability. Herein, a series of 2D oxygen vacancy-rich Co
3O
4-y−
x (
x = 1, 2 and 3) with well-defined 2D nanostructures, a high surface area and controllable oxygen vacancy contents (Co
3O
4-y) was synthesized via a facile self-assembly method and NaBH
4 reduction. When the 2D Co
3O
4-y−
x (
x = 1, 2 and 3) nanosheets are introduced as nanofillers in PEO-based SPEs, they can interact with the PEO to form a three-dimensional (3D) PEO/Co
3O
4-y film with uniform Li
+ distribution and vertical diffusion channels, as well as strong adsorption of NO
3− from LiNO
3 electrolyte salt at the defective sites. As a result, the PEO/Co
3O
4-y−2 film reached a high ionic conductivity of 4.9 × 10
−5 S cm
−1, high Li
+ a transference number of 0.51 and a wide electrochemical window over 4.6 V at 80 °C. The PEO/Co
3O
4-y−2 film enables the Li||PEO/Co
3O
4-y−2||LiFePO
4 cell to deliver a high reversible capacity of 117.7 mAh g
−1 at 2 C and to maintain 126.7 mAh g
−1 at 1 C after 250 cycles with an initial capacity retention of 87.9%.
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