Toward Stable Aluminum Metal Anodes in Nonaqueous Aluminum Batteries: Challenges and Design Strategies

ABSTRACT Nonaqueous rechargeable aluminum batteries have attracted interest for scalable energy storage, but their practical development remains constrained by the reversibility and stability of Al metal anodes. Rather than arising from isolated interfacial defects, Al‐anode failure is typically governed by coupled degradation processes. Persistent passivation and impedance buildup associated with native or dynamically reconstructed surface layers, corrosion in chemically aggressive electrolytes, and speciation‐ and transport‐dependent deposition instability can collectively drive rough, porous and filamentary growth. In solid and quasi‐solid systems, insufficient wetting, contact loss and chemo‐mechanical mismatch further aggravate polarization and current focusing. This review provides a focused, mechanism‐based synthesis of these degradation pathways and organizes stabilization strategies into four complementary domains: anode‐intrinsic optimization, interfacial engineering, electrolyte modification and solid/gel/quasi‐solid electrolyte design. Across these domains, we discuss how substrate structure, composition, and crystallography, surface activation and protective interphases, electrolyte speciation/formulation/additives and matrix/contact design can suppress parasitic reactivity, homogenize ion flux and current distribution and stabilize Al plating/stripping. We further summarize key evaluation and benchmarking considerations to distinguish genuine stabilization from conditional performance gains, and distill design principles for coordinated substrate−interface−electrolyte−contact optimization. Overall, this review establishes a rational design framework for durable and practically relevant Al metal anodes in nonaqueous aluminum batteries.