System versus charger in performance optimization of quantum batteries

Quantum batteries have emerged as promising devices that work within the quantum regime and provide energy storage and power delivery. In this work, we explore the interplay between the battery and charger Hamiltonians, focusing on controlling and minimizing the batterys intrinsic influence during the charging process. To this end, we introduce a tunable parameter that allows partial suppression of the batterys contribution, enabling a systematic study of its role in energy transfer. We examine several charging configurations: a non-interacting qubit battery driven by an interacting many-body charger, an interacting qubit battery energized by a non-interacting charger, and setups in which both the battery and the charger are interacting qubit chains. In all cases, the inclusion of a controllable counteraction, or anti-effect of the battery Hamiltonian, allows us to modulate the batterys internal dynamics during charging. Our results demonstrate a significant enhancement in both stored energy and charging power when the batterys influence is suppressed, emphasizing the critical role of the charger in optimizing performance. Notably, we find that incorporating the batterys countereffect consistently improves storage characteristics across all configurations, suggesting a novel avenue for designing highly efficient quantum batteries.