Abstract
Abstract In this work, an alternative fabrication process is implemented to fabricate a bioresorbable Na‐ion battery showing excellent electrochemical performance (discharge capacity of 5.1 mAh cm−2) and no toxicity after being disintegrated under in vivo conditions. Solely composed of biocompatible materials, the proposed all‐solid‐state rechargeable battery implanted under the skin is capable of disintegrating safely. The operating days and lifetime of this novel energy storage system are evidenced that after being implanted in artificial skin can be finely controlled by tuning the thickness of the encapsulation layer, rendering possible the design of “on‐demand” bio‐eliminable batteries that may operate days or several weeks. The toxicity tests and the lack of organ damage performed by ex vivo analyses after 3 months confirmed the safety of the approach. In addition, wireless recharge of the battery is demonstrated through the skin using an inductive charger to establish the proof‐of‐concept. Preliminary tests revealed that wireless recharge of the subcutaneous implanted battery is achieved in 30 min, and that recharge remains possible in 1 h for deeper implanted batteries. The high versatility of the concept is definitely appealing to address the various needs of the temporary medical device market.