Decoupling Chemo-Mechanical Failure and Interfacial Instability in Graphite/SiOx Anodes via Layered Electrode Architecture

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Abstract
SiOx material has been put into practical application with graphite material in lithium ion battery industries. To obtain high-performance graphite-SiOₓ laminate, layered electrode configurations including Gr/SiOx and SiOx/Gr were prepared. Compared to the randomly mixed SiOx&Gr architecture, it is found that layered configurations exhibit superior long-cycle stability and high rate capability. Integrated characterizations and kinetic analyses reveal that the layered structure effectively reconfigures stress transfer pathways, reduces electrode stress concentration, and improve the surface chemistry. Therefore, the electrode integrity and electrical contact are well preserved. Moreover, a thin and uniform SEI film is developed on the layered Gr/SiOx electrode due to the suppressed cross-talk between graphite and SiOx and the decreased interfacial side reactions. The full-cells made with the Gr/SiOx layered structure exhibit superior cycling stability and fast electrochemical kinetics. The assembled Gr/SiOx‖NCM811 full cell maintains a capacity of 131.56 mAh/g after 300 cycles at a 0.2C rate with a high reversible 102.83 mAh/g at 5C rate. The Gr/SiOx‖NCM523 pouch cell maintains a capacity retention rate as high as 80% after 400 cycles, exhibiting superior cycling stability. This work establishes a scalable electrode paradigm for the high-energy-density SiOx-graphite composite anode.

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