Digital badges may be virtually awarded by several organizations (for example educational insti- tutions) upon an individual's achievements. Internet technologies, such as user profiles on social media or web services, may be used to collect and present these digital badges. This thesis discusses the application of digital badges in knowledge management. More precisely, it is about the proof of personal expert-knowledge and competencies, acquired through informal learning. Whereas formal learning approaches are using a curriculum to define the learning path and certificates to proof learning achievements, a proof of additional competencies, such as experience in a particular topic or soft skills, is often missing. This thesis introduces a concept how digital badges will solve the problem of a missing proof of hidden knowledge. We discuss the approach based on an online knowledge-sharing platform. TechScreen is such a platform that allows users to submit problems (challenges) and to discuss about them, respectively to submit solution approaches. Our approach uses digital badges to image one's gain of knowledge during knowledge sharing on TechScreen. Based on this personal competence profile, TechScreen issues digital badges. As part of the research question of this thesis, we further defined a long-term study to evaluate whether digital badges are an adequate proof of hidden knowledge. Secondly, we conducted a questionnaire to evaluate the acceptance of digital badges and its resulting willingness to proactively share knowledge.