Comparing the Evolution of Lithium-Ion Cells across Energy, Power, Lifetime, and Temperature with the Enpolite Plot

Abstract

In the field of solar technologies, NREL has tracked the evolution of various technologies on the Best Research Cell Efficiency Chart for decades. This allows for a "sanity check" of a new technology, as there is a clear guideline for the entire solar field when a new technology has a significant advantage, even if it is small. In the battery field, however, many "wonder batteries" are presented that focus on only one indicator of battery performance, such as fast charging capability, while neglecting others such as energy density, cycle life, or operating temperature. This makes it difficult for even experts to evaluate new technologies.On the other hand, with new efforts by the battery community to create an open and shared battery data ecosystem, a whole new set of data can be leveraged to create better and more holistic comparisons of new technologies to the state of the art. In addition to the previous publication of the ENPOLITE plot (doi.org/10.1021/acsenergylett.1c00743) and on the website https://enpolite.org/, in this paper we show our extension of the work on the plot to include a time scale.The ENPOLITE plot is a highly informative tool for comparing the evolution of battery technology. At a glance, it provides crucial details such as capacity, cell format, cell chemistry, aging test duration, measurement temperature, specific power, energy density and achieved lifetime for each cell. In addition, the battery life coefficient derived from this plot allows comparison of lithium-ion batteries of different weights or volumes, capacities and cell chemistries.The ENPOLITE Plot combines multiple parameters to facilitate a thorough comparison of various battery degradations, making it an incredibly useful tool for battery researchers and developers. It not only displays cell-specific parameters during cycling, but also includes information on specific stored energy and storage temperature in a calendar format. This comprehensive approach allows researchers to identify trends and patterns in battery performance, helping to develop more efficient and durable battery technology.We hope to provide the battery community with a better tool for evaluating and ranking new technologies and improvements to existing battery types. Figure 1