The output voltage is an important parameter to evaluate performance of triboelectric nanogenerator (TENG). However, the voltage for contact-separation TENG is hardly to reach a higher value and commonly gives an asymmetric alternating voltage (current). When the upper electrode operates from separation to contact state, the voltage is mainly related to dielectric film thickness (Low voltage), while it operates from contact to separation state, the voltage is mostly depended on separate distance (High voltage). It is found that the output voltage is limited by the asymmetrical voltages because the Low voltage hardly pushes charges fully from one electrode to another electrode in large load situation. Two strategies are found. By increasing dielectric film thickness symmetrical output voltages are obtained and 2.7 times output energy are achieved. By using half-wave circuit to eliminate the low voltage restriction, 16.5 kV high voltage and 5 times output energy (1.862 mJ per cycle) are achieved. The improved voltage mechanism of contact-separation TENG in this work provides a basic scientific method for maximum energy output, which also can be used in other device improvement.

输出电压是评估摩擦纳米发电机（TENG）性能的重要参数。然而，用于接触分离的电压TENG几乎难以达到较高的值，并且通常给出不对称的交流电压（电流）。当上部电极从分离状态到接触状态工作时，电压主要与介电膜厚度（低电压）有关，而上部电极从接触状态到分离状态工作时，电压主要取决于分离距离（高电压）。已经发现，输出电压受到不对称电压的限制，因为在大负载情况下，低电压几乎不会将电荷从一个电极完全推向另一电极。找到了两种策略。通过增加介电膜的厚度，可以获得对称的输出电压，并获得2.7倍的输出能量。通过使用半波电路消除低电压限制，可实现16.5 kV高压和5倍的输出能量（每个周期1.862 mJ）。这项工作中改进的接触分离TENG的电压机制为最大的能量输出提供了一种基本的科学方法，也可用于其他器件的改进。