Universal power-efficiency trade-off in battery charging

Designing efficient and fast-charging batteries is an important goal in the field of energy, crucial for upgrading new energy vehicles and portable electronic devices such as smartphones. Here, we incorporate the concept of finite-time thermodynamics into studying the resistor-capacitor (RC) series circuit and obtain the time-dependence of charging efficiency and charging power. Through this exploration, essential thermodynamic constraints governing the charging process, including the trade-off relation between charging power and efficiency, are obtained. Moreover, we reveal the lower bound for charging time and the corresponding optimal charging strategy, and further demonstrate the power-efficiency trade-off relation in such an optimized strategy. Our findings shed new light on seeking optimal battery charging methods with nonequilibrium thermodynamics.