A safe and robust in-situ polymerized cementitious electrolyte coupled with NiCoS@CuCoS electrode for superior load-bearing integrated electrochemical capacitor.

Load bearing/energy storage integrated devices (LEIDs) featuring cementitious electrolytes have become ideal for large-scale energy storage. Nevertheless, the progression of LEIDs is still in its nascent phase and considerable endeavors concerning cementitious electrolytes and electrode materials are necessary to further boost the charge storage ability. Here, we propose a facile synchronous reaction method for preparing sodium acrylate (SA)-based in-situ polymerized cementitious electrolyte. The soft polymer network and hard cement matrix are interwoven together. The resulting cementitious electrolyte not only exhibits improved mechanical properties (flexural strength of 14.7 MPa and compressive strength of 44.7 MPa), but also possesses enhanced ionic conductivity (26.7 mS cm). Moreover, a core-shell NiCoS@CuCoS/NF heterostructure is synthesized on nickel foam (NF) substrate by hydrothermal assisted electrodeposition techniques, which showcases a remarkable capacitance of 5626.6 mF cm at 1 mA cm. As a proof, with integrated merits of the optimal cementitious electrolyte and NiCoS@CuCoS/NF electrode, the as-built LEID demonstrates a high energy density of 138.5 μWh cm at 0.75 mW cm and a cycling durability of 90.7 % after 8000 cycles, showing good practicability in lighting light-emitting diodes (LEDs) or driving a thermal hygrometer. Notably, the LEID can endure external forces without distinctly sacrificing electrochemical properties. This work provides insight into developing novel cementitious electrolytes and electrode materials toward superior LEIDs.