Achievable energy densities dominate important future research activities on battery technology. This book deduces in detail the future options for energy density enhancement of rechargeable battery cells and complete batteries. It connects rechargeability to energy density limits and gives a detailed argumentation on how and when battery energy densities will achieve their inherent limits.This work provides key insights for the future market for modern batteries and points readers towards future battery cell designs -- highlighting their limitations and potential advancements, and discusses which battery cell technologies will survive and dominate. It identifies the most promising candidates for achieving higher energy densities and explores the trade-offs between energy density, power density, lifetime, safety, and costs. It also investigates the influence of raw materials on energy densities and provides an overview of progress made in battery energy densities. Lastly, it expands the discussion to alternative energy storage systems, revealing a compelling vision for the future of energy storage.Precise Energy is a valuable resource for researchers and students of related fields, engineers and other professionals with corresponding background, and decision and policymakers interested in the evolving landscape of energy storage and its profound impact on our future.