Endowing an Intrinsic High‐Capacity Primary Thin‐Film Cathode With Cyclability

Abstract

ABSTRACT The rapid development of the Internet of Things (IoT) urgently demands high‐performance and process‐compatible integrated micro‐power sources. All‐solid‐state thin‐film batteries (ATFBs), which combine an all‐solid‐state architecture with on‐chip integration capability, are regarded as an ideal on‐chip power solution. However, their practical application is constrained by the low capacity of conventional cathode materials and the high‐temperature annealing process (>500°C) required for crystallization, which is incompatible with temperature‐sensitive integration processes. This study presents an annealing‐free Ag 2 O/V 2 O 5 composite thin‐film cathode, fabricated at room temperature by magnetron co‐sputtering, in which the nanoconfinement effect of the amorphous V 2 O 5 matrix effectively suppresses Ag 2 O particle agglomeration to endow the electrode with satisfactory cycling stability. The composite thin‐film cathode demonstrates excellent lithium storage performance, delivering an initial discharge capacity as high as 171.0 µAh cm −2 µm −1 (406.5 µWh cm −2 µm −1 ), which is approximately 2–3 times that of LiCoO 2 , while maintaining 73% capacity retention after 1000 cycles. When integrated into ATFBs, this cathode achieves 71% retention over 400 cycles and can successfully power an LED sensor and a motion sensor. This work provides a new pathway to overcome the challenges of energy density and process compatibility in microelectronic applications.