• • Transient primary batteries achieve energy densities up to 250 Wh kg−1 and discharge plateaus of 3.0–4.2 V, matching conventional lithium batteries while enabling complete biodegradation, critical for avoiding second removal surgeries.
• • Biodegradable gel electrolytes in flexible supercapacitors deliver specific capacitances of 100–200 F g−1 with capacitance retention >90% after 10,000 cycles, as reported in ACS Appl Mater Interfaces 2015, demonstrating mechanical robustness for dynamic tissues.
• • Fully biodegradable micro-supercapacitors (Adv Energy Mater 2017) exhibit areal capacitance of 10 mF cm−2 and can power transient electronics for hours, with complete degradation in phosphate-buffered saline within 4 weeks, validating transient operation.
• • Heterostructured MoO3-MoS2 composites (Small 2023) achieve high-performance biodegradable energy storage with specific capacity of 300 mAh g−1 at 0.5 A g−1, offering a viable anode material for transient secondary batteries.