A both microscopically and macroscopically intrinsic self-healing long lifespan yarn battery

Intrinsic self-healing is one essential feature for the next generation of flexible and wearable electronics. Previous studies on self-healing flexible energy storage have mainly focused on macroscopic self-healing and super-capacitors, whereas the microscopic self-healing and batteries utilization remain a challenge. Here we report a flexible and wearable aqueous lithium ion yarn battery by in-situ polymerization of calcium ion cross-linking sodium polyacrylate and sodium alginate self-healable hydrogel electrolyte. The microscopic self-healing contributes to cyclic stability of 5000 cycles with 70% capacity retention, and the macroscopic self-healing results in 8 times of complete breaking/healing with 68% capacity retention. Both performances outperform aqueous lithium ion batteries and even other aqueous batteries reported so far to the best of our knowledge. The unprecedented microscopically and macroscopically intrinsic self-healing-resulted fantastic lifespan of the yarn battery, together with its features of high capacity, fewest components and handy fabrication, make it promising in flexible and wearable electronics.