This review reports progress in solid electrolytes integrated into all-solid-state 2D and 3D lithium-ion microbatteries. The latest improvements, performance and challenges of the all-solid-state 2D and 3D structured microbatteries are analyzed.

This work reports the preparation of a three‐dimensional Si thin film negative electrode employing a porous Cu current collector. A previously reported copper etching procedure was modified to develop the porous structures inside a 9 μm thick copper foil. Magnetron sputtering was used for the deposition of an n‐type doped 400 nm thick amorphous Si thin film. Electrochemical cycling of the prepared anode confirmed the effectiveness of utilizing the approach. The designed Si thin film electrode retained a capacity of around 67 μAh cm⁻² (1675 mAh g⁻¹) in 100^th cycle. The improved electrochemical performance resulted in an enhancement of both areal capacity and capacity retention in contrast with flat and rough current collectors that were prepared for comparison.

The tetravalent cations with similar sizes (Zr ⁴⁺ , Hf ⁴⁺ ) supress the Ti ⁴⁺ reduction while the bulky divalent cations (Ca ²⁺ , Sr ²⁺ ) promote it even at relatively low concentrations.