This paper aims to focus on the design and analysis of a novel ring-based mono-stable energy-harvesting device that is considered as an alternative to the beam and tube models used thus far. The highly sensitive ring second flexural mode, when combined with the nonlinear external magnetic force, results in an ideal combination that yields increased frequency range, and can be considered as novel in the field of vibration-based energy harvesters. A mathematical model for the ring structure, as well as a model to generate nonlinear magnetic force that acts on the ring structure, is formulated. The discretized form of the governing equations is shown to represent a Duffing oscillator in the presence of an external magnetic field. The forms of the system potential energy, as well as the restoring force, are examined to ensure that the mono-stable behavior exists in the proposed model. Numerical predictions of time response, frequency response, phase diagram, and bifurcations map when the system is subjected to ambient harmonic excitation, have been performed for the purposes of gaining an insight into the dynamics and power generation of this new class of harvesters.