Carbon, with its excellent conductivity and structural stability, plays a crucial role in energy storage and conversion technologies and is considered an ideal choice in electrochemical energy storage for electrode materials. To address these needs and safeguard the environment, scientists have been investigating novel approaches to synthesis. In this field, molten salts or salt melts have emerged as a powerful and environmentally friendly alternative for synthesizing porous carbon materials with tunable chemical and structural properties. These salt systems can serve not only as solvents and reaction media but also as templates. Similar to traditional templating strategies, porous carbon materials synthesized using salt templates do not sacrifice carbon yield, but what sets them apart from traditional methods is that template removal can be achieved through deionized water washing. This article introduces a self-activation method that is applied to the preparation of carbon nanomaterials with high porosity and enormous specific surface area. The working principle, process steps, preparation characteristics, and research progress of this process are summarized, and its potential applications in next-generation electrochemical energy storage devices are discussed and envisioned.