  Strongly electric fish use gradients of ions within their bodies to generate
stunning external electrical discharges; the most powerful of these organisms,
the Atlantic torpedo ray, can produce pulses of over 1 kW from its electric
organs. Despite extensive study of this phenomenon in nature, the development
of artificial power generation schemes based on ion gradients for portable,
wearable, or implantable human use has remained out of reach. Previously,
inspired by the electric eel, we developed an artificial electric organ that
generated electricity from ion gradients within stacked hydrogels and, like the
eel, was optimized to deliver large voltages that exceeded 100 V. Due to its
high internal resistance, the current of this power source was, however, too
low to power standard electronics. Here we introduce an artificial electric
organ that takes inspiration from the unique morphologies of torpedo rays for
maximal current output. This power source uses a hybrid material of
hydrogel-infused paper to create, organize, and reconfigure stacks of thin,
arbitrarily large gel films both in series and in parallel. The resulting
increase in electrical power by almost two orders of magnitude compared to the
original eel-inspired design makes it possible to power electronic devices and
establishes that biology's mechanism of generating significant electrical power
can now be realized from benign and soft materials in a portable size.
