Engineering constraints in rechargeable batteries from material performance to full cell validation

High active-material capacity does not guarantee a durable or energy-dense rechargeable battery. This mini-review examines how electrolyte inventory, electrode loading, interfacial losses, and mechanical contact constrain the translation from material measurements to full cells. Lithium-based and sodium/potassium-ion systems provide reference cases, while magnesium, aluminum, and aqueous zinc receive focused analysis. A common accounting framework connects delivered energy to component mass and relates metal utilization to irreversible charge loss. Recent examples distinguish electrolyte-enabled magnesium reversibility from limited-inventory full-cell durability, identify electrolyte capacity and collector dissolution as separate constraints in aluminum batteries, and connect zinc deposition efficiency with gas generation and pouch-cell validation. These examples show why half-cell efficiency, symmetric-cell lifetime, and cathode-normalized capacity cannot be treated as interchangeable evidence of device performance. The review identifies reporting requirements that allow an engineering strategy to be evaluated under stated loading, electrolyte, temperature, and pressure conditions. Its contribution is a comparative interpretation of demonstrated trade-offs and remaining validation gaps, rather than an exhaustive ranking of battery chemistries.