Super‐Assembled Hierarchical Cellulose Aerogel‐Gelatin Solid Electrolyte for Implantable and Biodegradable Zinc Ion Battery

Transient devices represent an emerging type of electronics whose main characteristic is the constituent materials that could fully or partially dissolute or disintegrate by chemical or physical processes after completing the mission, and are considered as new research directions for implantable devices. However, research on transient devices is still in its infancy and there are many challenges to overcome, especially the development of transient energy devices is relatively slow. Here, an implantable, biodegradable transient zinc ion battery (TZIB) that assembles a carefully designed cellulose aerogel‐gelatin (CAG) solid electrolyte. The new fully degradable CAG solid electrolyte allows TZIB to achieve controlled degradation and stable electrochemical performance, at the same time maintaining excellent mechanical properties. The entire battery device can be completely degraded within 30 days in the buffered proteinase K solution. More importantly, TZIB has excellent electrochemical performance while meeting controlled degradation, providing a specific capacity of 211.5 mAh g−1 at a current of 61.6 mA g−1 and a wide voltage range (0.85–1.9 V). These results demonstrate the potential of TZIB in future clinical applications and provide a new platform for transient electronic technology. An implantable, rechargeable transient battery is successfully fabricated by using a facilely designed cellulose aerogel‐gelatin solid electrolyte with excellent biocompatibility and complete degradability. This work provides new opportunities for future self‐powered transient electronics for applications in medical implants, disease diagnosis, and treatment.