Conductive Porous Solid Framework Mechanically Stabilized Si Anode.

Micron-sized Si anodes garner renewed attention due to their advantages of low cost, small specific surface area, and high energy density. However, micron-sized Si anodes undergo significant volume changes during lithiation/delithiation, leading to particle cracking and pulverization. This study employs the tape casting method and ultrafast high-temperature sintering technology to construct a porous sheet, within which a solid framework constrains the Si particles. In rate performance tests, when the current density rises to 1 A g, the micron-sized Si in the porous sheet demonstrates a delithiation capacity of 2145 mAh g, compared to 113 mAh g for the pristine Si, showing efficient ion and electron conductive pathways in the framework. When cycled at 0.3 A g, the delithiation capacity of the ball-milled micron-sized Si in the porous sheet is 1496 mAh g after 100 cycles, in contrast to 95 mAh g for the pristine Si. The enhanced cycling stability of Si in the porous sheet results from the strong mechanical constraint imposed by the solid framework, which suppresses volume changes, inhibits particle cracking, and reduces solid electrolyte interphase growth. This strategy of constructing porous sheets and utilizing solid-solid bonding to constrain Si particles represents a novel approach for Si anode modification.