Hydrovoltaic electricity generators (HEGs), powered by ubiquitous water evaporation, are emerging due to their high spontaneity and continuity. However, the current performance of most HEGs is restricted to 50.00 μA cm⁻², far from commercial applications. Herein, we propose an ion-engine HEG by establishing a concentration gradient of an ionisation group in hydrogels along the direction of ion migration. The distinctively designed ion gradient acts as an engine to accelerate ion migration by enhancing diffusion, hence increasing the generated current. Notably, the ion-engine HEG generates a record-breaking current density of 466.75 μA cm⁻², 10 to 100 times higher than those of previously reported HEGs. The ion-engine HEG possesses the lowest internal resistance, which is the closest to that of commercial products. In addition, the high transparency, flexibility, and customisability of hydrogels offer HEGs a wide range of applications, such as night-time lighting, sweat monitoring, and powering small unmanned boats. These findings provide a fresh perspective on high-performance HEGs, which have great potential to serve energy technology and intelligent life.

中文翻译：

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水凝胶中的离子发动机促进水力发电

由无处不在的水蒸发提供动力的水力发电机 (HEG) 由于其高度的自发性和连续性而正在兴起。然而，目前大多数HEGs的性能仅限于50.00 μA cm ^-2，远非商业应用。在此，我们通过在水凝胶中沿离子迁移方向建立电离基团的浓度梯度，提出了一种离子引擎 HEG。独特设计的离子梯度充当引擎，通过增强扩散来加速离子迁移，从而增加产生的电流。值得注意的是，离子引擎 HEG 产生了破纪录的 466.75 μA cm ^{−2电流密度}, 比以前报道的 HEGs 高 10 到 100 倍。离子发动机HEG具有最低的内阻，最接近商业产品。此外，水凝胶的高透明度、柔韧性和可定制性为 HEG 提供了广泛的应用，例如夜间照明、汗液监测和为小型无人船提供动力。这些发现为高性能 HEGs 提供了全新的视角，具有为能源技术和智能生活服务的巨大潜力。