Coherent catalyst induced stabilization of ergotropy in open quantum batteries

Environmental dissipation and thermal fluctuations fundamentally constrain the extractable work and long-time stability of open quantum batteries. To mitigate dissipation-induced energy degradation without external driving protocols, we propose a cavity-mediated hybrid quantum battery coupled to an auxiliary coherent qubit. Using the Lindblad master equation and ergotropy analysis, we show that coherent interference between different interaction channels generates a decoherence-free-like invariant subspace that suppresses relaxation-induced energy leakage and stabilizes the steady-state ergotropy. The resulting protection mechanism remains effective under strong dissipation and finite-temperature conditions, indicating that interference-assisted coherent control may provide a feasible strategy for robust quantum energy storage in nonequilibrium open systems.