In 1859, the French physicist Gaston Plante invented the first rechargeable lead-acid battery at the Paris Conservatory of Arts and Crafts. Unlike previous batteries, which could only be used until their chemical reactants were exhausted, Plante's device could be reversed by passing a current through it in the opposite direction, restoring its ability to produce electricity. This invention in Paris created the first practical method for storing electrical energy and releasing it on demand, a principle that remains the basis for most automotive batteries today.

The lead-acid battery's ability to store and release electrical energy on demand reinforced the metaphor of accumulated inner power that had been developing in poetry since the voltaic pile. In the literary culture of Second Empire France, the idea of stored, reusable energy resonated with themes of endurance, resilience, and the capacity for renewal that pervade the poetry of Charles Baudelaire and the Parnassian movement. The battery's cyclical nature, charging and discharging, also suggested organic metaphors of breath, pulse, and rhythm that influenced the developing free verse movement.