The article "True Performance Metrics in Electrochemical Energy Storage" by Y. Gogotsi and Patrice Simon discusses the challenges in accurately assessing the performance of electrochemical capacitors (ECs) and batteries. The authors highlight that exceptional claims about electrode materials often do not translate to practical device performance when all components are considered. They emphasize the importance of using Ragone plots, which show both power density and energy density, to compare these devices. However, they argue that reporting performance metrics per weight alone can be misleading, as it does not account for the weight of other device components. The authors also point out that low-density materials like graphene and nanotubes can have high gravimetric energy densities but lower volumetric densities, which are more relevant for practical applications. They advocate for consistent reporting of performance metrics and the creation of benchmarking facilities to facilitate the introduction of new materials and solutions for electrochemical energy storage.The article "True Performance Metrics in Electrochemical Energy Storage" by Y. Gogotsi and Patrice Simon discusses the challenges in accurately assessing the performance of electrochemical capacitors (ECs) and batteries. The authors highlight that exceptional claims about electrode materials often do not translate to practical device performance when all components are considered. They emphasize the importance of using Ragone plots, which show both power density and energy density, to compare these devices. However, they argue that reporting performance metrics per weight alone can be misleading, as it does not account for the weight of other device components. The authors also point out that low-density materials like graphene and nanotubes can have high gravimetric energy densities but lower volumetric densities, which are more relevant for practical applications. They advocate for consistent reporting of performance metrics and the creation of benchmarking facilities to facilitate the introduction of new materials and solutions for electrochemical energy storage.