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Classic chemical sensors integrated in phones, vehicles, and industrial plants monitor the levels of humidity or carbonaceous/oxygen species to track environmental changes. Current projections for the next two decades indicate the strong need to increase the ability of sensors to sense a wider range of chemicals for future electronics not only to continue monitoring environmental changes but also to ensure the health and safety of humans. To achieve this goal, more chemical sensing principles and hardware must be developed. Here, a proof‐of‐principle for the specific electrochemistry, material selection, and design of a Li‐garnet Li₇La₃Zr₂O₁₂(LLZO)‐based electrochemical sensor is provided, targeting the highly corrosive environmental pollutant sulfur dioxide (SO₂). This work extends the prime use of LLZO as a battery component as well as the range of trackable pollutants for potential future sensor‐noses. Novel composite sensing‐electrode designs using LLZO‐based porous scaffolds are employed to define a high number of reaction sites, and successfully track SO₂at the dangerous levels of 0–10 ppm with close‐to‐theoretical SO₂sensitivity. The insights on the sensing electrochemistry, phase stability and sensing electrode/Li⁺electrolyte structures provide first guidelines for future Li‐garnet sensors to monitor a wider range of environmental pollutants and toxins.

The introduction of new, safe, and reliable solid‐electrolyte chemistries and technologies can potentially overcome the challenges facing their liquid counterparts while widening the breadth of possible applications. Through tech‐historic evolution and rationally analyzing the transition from liquid‐based Li‐ion batteries (LIBs) to all‐solid‐state Li‐metal batteries (ASSLBs), a roadmap for the development of a successful oxide and sulfide‐based ASSLB focusing on interfacial challenges is introduced, while accounting for five parameters: energy density, power density, longterm stability, processing, and safety. First taking a strategic approach, this review dismantles the ASSLB into its three major components and discusses the most promising solid electrolytes and their most advantageous pairing options with oxide cathode materials and the Li metal anode. A thorough analysis of the chemical, electrochemical, and mechanical properties of the two most promising and investigated classes of inorganic solid electrolytes, namely oxides and sulfides, is presented. Next, the overriding challenges associated with the pairing of the solid electrolyte with oxide‐based cathodes and a Li‐metal anode, leading to limited performance for solid‐state batteries are extensively addressed and possible strategies to mitigate these issues are presented. Finally, future perspectives, guidelines, and selective interface engineering strategies toward the resolution of these challenges are analyzed and discussed.

Specialized hardware for neural networks requires materials with tunable symmetry, retention, and speed at low power consumption. The study proposes lithium titanates, originally developed as Li‐ion battery anode materials, as promising candidates for memristive‐based neuromorphic computing hardware. By using ex‐ and in operando spectroscopy to monitor the lithium filling and emptying of structural positions during electrochemical measurements, the study also investigates the controlled formation of a metallic phase (Li₇Ti₅O₁₂) percolating through an insulating medium (Li₄Ti₅O₁₂) with no volume changes under voltage bias, thereby controlling the spatially averaged conductivity of the film device. A theoretical model to explain the observed hysteretic switching behavior based on electrochemical nonequilibrium thermodynamics is presented, in which the metal‐insulator transition results from electrically driven phase separation of Li₄Ti₅O₁₂and Li₇Ti₅O₁₂. Ability of highly lithiated phase of Li₇Ti₅O₁₂for Deep Neural Network applications is reported, given the large retentions and symmetry, and opportunity for the low lithiated phase of Li₄Ti₅O₁₂toward Spiking Neural Network applications, due to the shorter retention and large resistance changes. The findings pave the way for lithium oxides to enable thin‐film memristive devices with adjustable symmetry and retention.