Predominant global assessments indicate that demand-side solutions could reduce GHG emissions by 40%–70% by 2050, but little is known about the costs of implementing them at scale. This is a critical knowledge gap: cost is a key factor in policy and investment decisions. Demand-side solutions are becoming increasingly crucial amid rising global energy prices, but in the absence of comparable cost metrics, they are rarely evaluated alongside supply-side resources. This paper addresses this gap by presenting a method for evaluating the costs of demand-side solutions. It includes a set of energy-service-specific metrics across the building, transportation, food, and industrial sectors, along with quantitative estimates and comparisons with supply-side solutions. Using a consistent framework, we analyzed case studies implemented across various global regions and estimated their potential for energy reductions along with associated costs and CO2 emissions mitigation. Compared with baselines, we find that adopters of alternative demand-side solutions can achieve the same energy-service level while realizing lifetime cost savings of up to 94% with certain solutions. The building sector’s potential savings in energy use, emissions, and costs range from 10% to 94%; the industry sector can reach 60% at the plant level, depending on plant sizes and measures. We also observed potential emission savings, but with cost increases in the transportation and food sectors, both of which are highly context dependent. Compared with the benchmark costs of supply-side solutions, almost 98% of the selected demand-side solutions in this study are cheaper than the 2022 wholesale peak electricity price in Europe, making them valuable resilience hedges and no-regret options. A comprehensive evaluation of potential costs and savings for demand-side energy solutions, along with a comparison with supply-side options, helps bridge the knowledge gap for informed decision-making and supports climate action among policymakers, businesses, and consumers.
Hydrogen is poised to underpin the global energy transition, yet today’s production, storage, and distribution remain constrained by carbon-intensive processes and costly infrastructure. Chemical hydrogen carriers, including ammonia, methane, methanol, and liquid organic hydrogen carriers (LOHCs), address these barriers by enabling high-density hydrogen storage, safer handling, more practical transport, and on-demand hydrogen release. This review critically assesses recent advances in catalytic hydrogen release from carriers across thermally driven, electrically driven, and light-driven platforms. Rather than cataloguing isolated catalyst examples, we organize the discussion around how each energy input creates distinct requirements for bond activation, intermediate stabilization, poisoning suppression, and product desorption. We synthesize mechanistic insights into carrier-specific elementary steps, working active-site motifs, dynamic reconstruction, and energy-delivery pathways, and evaluate how these insights guide catalyst design, reactor engineering, and system integration. Particular emphasis is placed on connecting design strategies to the carrier reactions they enable, including nitrogen recombination in ammonia decomposition, CO suppression in alcohol reforming, ensemble-size control in LOHC dehydrogenation, and bias-assisted water or carrier activation in electroreforming. Looking forward, advances in materials integration, hybrid catalytic architectures, operando characterization, and AI-assisted process control are expected to accelerate the development of selective, durable, and energy-efficient carrier-to-hydrogen technologies.
The primary limitation on the efficiency of perovskite-organic tandem solar cells (TSCs) is that the low-band-gap (LBG) organic subcells generate a lower photocurrent density than the wide-band-gap (WBG) perovskite subcells. This limitation arises from significant overlap in their external quantum efficiency (EQE) spectra near the band-gap edge of the perovskite films. Consequently, it is crucial to develop efficient near-infrared (NIR) acceptors. In this study, we develop an LBG acceptor (Zh-F) that exhibits improved NIR light absorption with a photoresponse extending beyond 1,000 nm when blended with the donor material PM6. Notably, incorporating Zh-F as a third-component acceptor into the PM6:BTP-eC9 system results in ternary organic solar cells (OSCs) with increased photocurrent density in the NIR region attributed to improved EQEs outside the overlapping wavelength range. As a result, by integrating this ternary LBG organic subcell with a 1.82 eV WBG perovskite subcell, the perovskite-organic TSCs achieve an efficiency of 27.35%.
Solid oxide electrolysis cells (SOECs) offer efficient hydrogen production, but their commercialization is limited by rapid cell degradation under high-temperature, high-steam operation. While material innovations show promise, scaling such approaches to industrial-size stacks remains challenging due to spatial inhomogeneity in reaction environments. Here, a slit-sheet stack architecture is introduced to passively regulate mass transfer and homogenize reaction fields without altering cell materials. Strategically patterned slits precisely control fuel supply and diffusion, which suppresses inlet-localized physical gradients and stabilizes the electrode microstructure, thereby enhancing spatial utilization of large-area cells. Experimental demonstrations under harsh conditions reveal a remarkable reduction in voltage degradation, representing the most effective mitigation of stack-level degradation reported so far, supported by flow visualization, multiphysics simulations, and microstructural analysis. This mass transfer control strategy provides a practical, scalable solution for improving SOEC durability and represents a critical step toward the deployment of robust electrolysis systems.
Heat accumulation remains a major threat to efficiency and operational stability as metal-halide perovskite photovoltaics are nearing commercial deployment. This perspective analyzes heat generation, consequences, and mitigation in representative 3D perovskite photovoltaics through a “source-implication-intervention” framework. We first examine waste heat from bias- and architecture-dependent optical and electrical losses, emphasizing reverse-bias hot spots and the intrinsically low thermal conductivity of soft, anharmonic lattices. We then discuss temperature-induced performance losses arising from recombination and diode characteristics, together with coupled degradation involving ion migration, interfacial reactions, electrode diffusion, and additive redistribution in charge-transport layers. Finally, thermal-management strategies are assessed, including thermally conductive additives, heat-radiation structures, interface engineering, functional encapsulation with conductive fillers or phase-change materials, and radiative-cooling covers that enhance mid-infrared emission with minimal optical loss. System-aware opportunities are further identified for tandem, flexible, and building-integrated perovskite photovoltaics.
Next-generation batteries demand architectural innovations that overcome the design limits of electrochemistry alone in conventional lithium-ion batteries (LIBs). This review summarizes architectural design strategies for LIBs and emerging battery systems, classifying them into 1D fiber-based, 2D planar, and 3D architectures. 1D designs, such as coaxial fibers, twisted assemblies, and winding configurations, offer flexibility and mechanical resilience for wearable and microscale batteries. 2D architectures, including interdigitated, pillar-based, and mesh frameworks, are reviewed alongside deformable (serpentine and origami/kirigami) and nature-inspired (e.g., accordion-like) geometries that enhance stretchability and flexibility while preserving electrochemical performance. 3D structural batteries, focused on volumetric design and energy densification, are examined for their potential to combine mechanical resilience with electrochemical functionality. Each architectural class is assessed for its design principles, performance trade-offs, and fabrication feasibility. By correlating architectural designs with advancements in additive manufacturing, this review outlines pathways to address electro-chemo-mechanical coupling challenges and guide the development of next-generation architected batteries.
Perovskite/silicon tandem solar cells face challenges when moving from planar glass to submicron-textured silicon substrates, primarily due to non-uniform buried interfaces that disrupt structural integrity and charge transport. In this study, we introduce an asymmetric phosphonic acid-based self-assembled monolayer (SAM) containing a thiophene functional group that can transcend the heterogeneity of submicron-textured substrates. This SAM molecule enables robust anchoring on pyramidal submicron structures, forming a stable and uniform interface between the perovskite layer and the textured silicon substrate. The significantly enhanced interaction of the molecule on the textured substrate results in exceptional interface passivation and low contact resistivity, minimizing non-radiative recombination and carrier transport losses. Leveraging this interface, our perovskite/silicon tandem devices achieved a certified stabilized power conversion efficiency of 34.15%, demonstrating a reliable and applicable strategy for obtaining efficient textured tandem devices. This work highlights the critical interplay between substrate topography, SAM molecular design, and interfacial energetics.
Sulfide-based all-solid-state batteries (ASSBs) offer high-energy and safe energy storage, yet their performance remains limited by the structural instability of conventional crystalline cathodes and poor interfacial compatibility with sulfide solid electrolytes (SEs). Herein, we propose a synergistic cathode design integrating interfacial quasi-homogenization, structural amorphization, and anion-enrichment regulation, using titanium sulfides as a proof-of-concept system. This strategy enables insertion-dominated cation-anion multi-electron redox while promoting a chemically compatible interface and improved deformation accommodation, thereby maintaining interfacial contact during chemo-mechanical evolution and suppressing parasitic reactions. Without surface coatings or multilayer SE architectures, the selected TiS3-based composite cathode delivers an ultrahigh capacity above 550 mAh g−1, a specific energy exceeding 1,000 Wh kg−1, and retains 390 mAh g−1 over 2,800 cycles at 2.0 A g−1 with ∼90% capacity retention, surpassing many reported layered oxide-based cathodes. This work bridges anion chemistry, structural disorder, and interfacial stability, offering a design principle for high-performance sulfide ASSBs.
Trace iron (Fe) impurities pose a challenge in alkaline water electrolysis (AWE) and can significantly impact long-term performance, yet their comprehensive system-level effects remain poorly understood. Here, we present the mechanistic roles of Fe in AWE, using combined rotation disk electrode studies, zero-gap cell measurements, and durability tests up to 1,000 h. Fundamental electrochemistry shows that Fe deposition proceeds through a solution-mediated pathway, with dendritic growth triggered under specific mass-transport and potential conditions. In single-cell operation, Fe incorporation substantially enhances nickel (Ni)-based anode activity by forming highly active Ni-Fe oxyhydroxides, while cathodic Fe forms either thin films or dendrites, depending on potential, surface morphology, and electrolyte distribution. Although dendrites do not degrade hydrogen evolution performance up to 1,000 h, they reveal partial intrusion into the separator, indicating a potential durability risk. We identify five governing factors controlling Fe dendrite formation and provide design principles for impurity-resilient AWE systems.
Defect passivation in high-efficiency perovskite solar cells increasingly demands molecular strategies that reconcile strong coordination with interfacial robustness under operational stress. Here, we introduce a steric-gated dual-site chelation concept enabled by 2,2′-(adamantane-1,3-diyl)diacetic acid (ADA-DA), in which bidentate carboxymethyl coordination is synergistically coupled with a rigid three-dimensional steric scaffold. This design simultaneously stabilizes undercoordinated Pb defect motifs and regulates local interfacial packing during rapid vacuum-flash crystallization, suppressing both non-radiative recombination and defect-mediated instability. As a result, inverted perovskite solar cells achieve a certified stabilized efficiency of 27.10%, with a peak value of 27.39%, alongside markedly improved device-to-device uniformity. Importantly, the same molecular strategy translates to large-area bifacial modules exceeding 22% on both sides, enabling stable power output with 99.6% retention over 5,000 h of continuous illumination. This work establishes steric-gated dual-site chelation as a generalizable molecular design principle for simultaneously advancing efficiency, reproducibility, and operational durability in scalable perovskite photovoltaics.
Halide materials have emerged as a promising solid electrolyte candidate for all-solid-state batteries owing to their high ionic conductivity and tunable electrochemical stability. Beyond this established role, they also offer an underexplored opportunity to contribute to energy storage as potential capacity contributors through their intrinsic redox chemistry. Herein, we synthesize the nascent field of halide redox chemistry, spanning both metal cations and halogen anions, and identify a core design principle that involves strategically matching the reversible redox voltage window of halides to the operating voltage of high-capacity electrodes. Beyond cation-centric redox, we elucidate the distinct reversibility of halogen anions (Cl, Br, and I) and illustrate their role in enhancing battery performance. By extending the function of halides from ion transport to coupled redox participation, this perspective outlines new directions for the design of next-generation all-solid-state batteries.
Concentrated aqueous electrolytes have emerged as a central strategy for stabilizing high-energy multivalent batteries, yet their design has largely relied on the presumption that increased additive content ensures stronger interfacial enrichment. Here, we show that this assumption does not hold universally: in AlCl3-ChCl hybrid electrolytes, choline cations become sequestered in the bulk phase through selective coordination with polychloroaluminate species ([Al(H2O)xCly]3−y), where the hydroxyl group of choline acts as an anchoring site. Consequently, excessive additive levels diminish polyiodide confinement and accelerate capacity fading, whereas an intermediate regime (3Al + 1Ch) achieves optimal interfacial accessibility, enabling 260 mAh g−1 at 0.5 A g−1 and stable cycling over 1,100 cycles at 2 A g−1. These findings introduce a concentration-guided interfacial design framework that identifies a functional concentration window to balance bulk coordination and interfacial enrichment, informing the design of durable, high-rate multivalent battery electrolytes.
Monolithic perovskite/silicon tandem solar cells require fast, inline-capable metrology to control subcell current matching during production. Here, we present an electrical transient method that extracts both subcell photocurrents from a single measurement on a finished tandem within milliseconds, without spectral modification. The approach exploits the silicon subcell’s capacitive charge reservoir and millisecond carrier lifetime—a brief forward pre-bias charges the reservoir, and a voltage step triggers a current overshoot. This overshoot reveals a perovskite-limited plateau followed by steady-state silicon limitation upon reservoir depletion, yielding both currents from one transient. An analytical model and Sentaurus TCAD simulations quantitatively predict the transient behavior. Validation on laboratory-scale and full-size industrial cells shows excellent agreement with spectrometric characterization while reducing measurement time from hours to milliseconds. The method integrates into standard high-throughput inline reverse j-V routines, minimally perturbs the perovskite subcell, and extends to other multijunction architectures combining direct and indirect semiconductors.
The utilization of CO2 provides a decarbonization pathway for hard-to-abate emissions, with solid-oxide and low-temperature electrochemical CO2 conversion offering routes to value-added chemicals. Unfortunately, CO2 sources are dilute and contain reactive impurities (NOx/SOx/O2) that influence electrolyzer performance. Research has then focused on understanding the implications of impurities on operation and designing catalyst structures that tolerate impure feeds. High feed tolerances would be promising as electrolyzers could then be co-located with point-source emissions and avoid pre-processing. However, electrolyzers operated with dilute or impurity-tolerant feeds merely transfer separation burdens downstream. Sulfur limits for methanol or Fischer-Tropsch synthesis are more stringent than the electrolysis step, while separating CO/N2 downstream is more complex than separating CO2/N2 upstream. Last, post-electrolysis oxygen impurities may pose flammability risks with by-product H2. In this perspective, we critically examine CO2 feedstocks and invoke a higher-level discussion reflecting where reactive impurities should be addressed in the electrochemical value chain.
