Design of high-energy-density lithium batteries: Liquid to all solid state

With the rising demand of lithium batteries from application fields including electric vehicles (EVs) and various electric aircrafts, it is imperative to greatly enhance the energy density of lithium batteries by rational design. However, there is still a lack of design roadmap for high-energy-density lithium batteries, largely owing to the uncertain selections of electrochemically active materials and the complicated relationships of diverse factors. In this article, based on the discussion of effects of key components and prototype design of lithium batteries with different energy density classes, we aim to tentatively present an overall and systematic design principle and roadmap, covering the key factors and reflecting crucial relationships. This article starts from the fundamental principles of battery design, and the effects of cathode, anode, electrolyte, and other components to realize high-energy-density lithium batteries have been discussed. Based on the prototype design of high-energy-density lithium batteries, it is shown that energy densities of different classes up to 1000 Wh/kg can be realized, where lithium-rich layered oxides (LLOs) and solid-state electrolytes play central roles to gain high energy densities above 500 Wh/kg. Lithium batteries are thus categorized according to different energy density classes, with available component options, to meet their most suitable application scenes.