Nano GeSe2/C anchored in carbon sponge skeleton for free-standing flexible lithium-ion battery electrodes

As a typical conversion alloyed anode material , Germanium selenide (GeSe 2 ) exhibits isotropic lithiation behavior and high theoretical charge-discharge specific capacity. However, pure GeSe 2 anode faces significant volume expansion (∼250 %−360 %) and further exploration is needed in the preparation of flexible electrode materials and structural design. Herein, a simple strategy is designed to load GeSe 2 /C-2 nanoparticles with porous carbon-coated structure on a flexible cross-networking substrate. The 3D network substrate is composed of highly conductive carbon nanotubes and adhesive cotton cellulose fibers. A two-step method involving coating and cross-linking is designed to achieve the fabrication of self-supporting flexible electrodes. As an anode for LIBs , the one layer GeSe 2 discs with ∼0.65 mm thickness manifest capacities of 827.1, 744.4, 676.3, and 472.9 mAh g −1 at 0.1, 0.2, 0.5, and 1 A g −1 , respectively. This superior Li + storage performance can be attributed to the positive collective impact from the integration of nano-scale material, low crystalline properties, and carbon sponge skeleton. Furthermore, the GITT tests indicate that the diffusion coefficient of Li + in the GeSe 2 -based electrodes ranged from 10 −15 to 10 −12 cm 2 /s, and the thickness of the flexible electrode (including two layers) has a negligible impact on its electrochemical performance.