Li-ion batteries (LIBs) have become the preferred choice in electric vehicles (EVs) for reducing CO2 emissions, enhancing energy efficiency, and enabling rechargeability. They are extensively used in mobile electronics, EVs, grid storage, and other applications due to their high power, low self-discharge rate, wide operating temperature range, lack of memory effect, and environmental friendliness. However, commercial LIBs face safety and energy density challenges, primarily due to volatile and flammable liquid electrolytes and moderate energy densities. To address these issues, advanced materials are being explored for improved performance in battery components such as the anode, cathode, and electrolyte. All-solid-state batteries (ASSEBs) emerge as a promising alternative to liquid electrolyte LIBs, offering higher energy density, better stability, and enhanced safety. Despite challenges like lower ionic transport, ongoing research is advancing ASSEBs’ commercial viability. This paper critically reviews the state of the art in ASSEBs, including electrolyte compositions, production techniques, battery management systems (BMSs), thermal management systems, and environmental performance. It also assesses ASSEB applications in EVs, consumer electronics, aerospace, defense, and renewable energy storage, highlighting the potential for a more sustainable and efficient energy future.