Lithium batteries.
According to the official website of the voice actor, we learned that the s2 epilogue of the voice actor uses lithium batteries. The advantage of using lithium batteries is that they are rechargeable and have low leakage current.
A microphone, also called a microphone, is an electroacoustic equipment, a microphone and a transducer for acoustic-electrical conversion. It uses sound waves to act on electroacoustic components to generate voltage, then converts it into electrical energy.