Confining Nano-GeS2 in Cross-Linked Porous Carbon Networks for High-Performance and Flexible Li-Ion Battery Anodes

As anode materials for lithium-ion batteries (LiBs), GeS2 has attracted considerable attention owing to its high theoretical capacity. Nevertheless, pulverization of GeS2 during the lithiation/delithiation process impedes its practical applications. Hybrid cross-linking with the second phase material is an effective strategy to improve the charge/discharge cycling performance. Herein, a high-capacity, long cycle-life nano-GeS2/carbon (GeS2/C) composite was facilely synthesized via the solid-state ball milling reaction. GeS2/C was then used to construct the three-dimensional (3D) flexible electrode. In this way, the flexible electrode with nano-GeS2/C particles confining in porous carbon networks exhibited improved reversible capacity and cycling performance, thanks to the unique confinement cellular structure. For instance, the flexible electrode with ∼500 μm thickness delivered capacities of ∼991, ∼888, ∼737, and ∼604 mA h g–1 at 0.1, 0.2, 0.5, and 1 A g–1, respectively. Upon stacking into two layers of the GeS2/C flexible electrode, the increased thickness displayed no effects on its diffuse-controlled capacity ratio and Li+ diffusion coefficient. This work provides a new strategy to stabilize germanium chalcogenides for LiB anodes with enhanced performance and sheds light on the preparation of other types of 3D flexible electrodes.