Solid-state batteries: a new frontier for robotics

1 Introduction

The rapid advancement of robotics—from autonomous mobile platforms and humanoid systems to soft, bioinspired machines—has placed unprecedented demands on portable energy storage. As robots transition from controlled industrial environments to unstructured, human-proximate settings, the limitations of conventional lithium-ion batteries (LIBs) have become increasingly apparent. Safety concerns arising from flammable organic liquid electrolytes, restricted energy densities that curtail operational endurance, and rigid cell geometries that constrain design freedom collectively represent critical bottlenecks in the evolution of next-generation robotic systems.

The scale of this challenge is set to grow dramatically. The global robotics market, valued at approximately $90 billion in 2024, is projected to reach approximately $416 billion by 2035, representing a compound annual growth rate (CAGR) of approximately 15% (Figure 1a) (GlobalData, 2025; Precedence Research, 2025). Service and mobile robots—the segments most dependent on advanced battery technology—are among the fastest-growing subsectors, with 200,000 professional service robots sold in 2024 alone (IFR, 2025). This explosive growth implies a correspondingly rapid increase in demand for robotic power sources that are safe, energy-dense, and geometrically versatile.

A critical but underappreciated aspect of this demand concerns the cumulative battery consumption of individual robots over their operational lifetimes. Although a single robotic battery pack is modest in capacity (typically 2–3 kWh) (Bonnen Battery, 2024), commercial robots operating in hot-swap configurations—where depleted battery packs are replaced with freshly charged ones to enable near-continuous operation—subject each pack to 3–4 full charge–discharge cycles per day. At this intensity, a nickel–manganese–cobalt (NMC) pack with a rated cycle life of 1,500 cycles requires replacement approximately once per year. Over a 7–10 years robot service life, a single machine may therefore consume 20–30 battery packs, amounting to a cumulative battery capacity of 60–88 kWh—equivalent to the entire battery of a passenger electric vehicle such as the Tesla Model 3 (60 kWh) or Model Y (75 kWh) (Figure 1b). This analysis reveals that the robotics sector’s per-unit battery demand is far larger than the nameplate capacity of individual packs would suggest, and that improvements in cycle life and safety—core advantages of solid-state technology—carry disproportionate economic and environmental value in robotic applications. The estimate is, of course, sensitive to the assumed cycle life: under a more conservative 1,000-cycle scenario, cumulative consumption rises to ∼90–130 kWh, while a 2,000-cycle scenario reduces it to ∼45–66 kWh. In all realistic ranges, however, the per-robot cumulative demand remains on the order of one passenger EV battery, preserving the qualitative conclusion. The 3–4 cycle-per-day assumption can be reconstructed from a transparent duty-cycle model: commercial autonomous mobile robots (AMRs) in logistics, intralogistics, and hospitality applications typically operate 12–20 h per day, and each 2–3 kWh pack sustains 4–6 h of active runtime, yielding three to four full pack rotations per 24-h shift cycle (Bonnen Battery, 2024). Annual replacement at 1,500 rated cycles follows arithmetically: 1,500 cycles ÷ 3.5 cycles day^-1 ≈ 1.17 years, which is consistent with field-reported pack-swap intervals in 24/7 fulfillment fleets such as those documented in service-robot deployment statistics (IFR, 2025). These are deliberately conservative round-number estimates; the cumulative-consumption conclusion holds across the realistic envelope of 2–5 cycles per day and 1,000–2,000 rated cycle life, as already captured by the sensitivity analysis above.

Solid-state batteries (SSBs), which replace the liquid electrolyte with a solid ionic conductor, have emerged as a transformative technology that could address these challenges simultaneously (Janek and Zeier, 2016). The inherent non-flammability of solid electrolytes eliminates the risk of thermal runaway—a paramount concern for robots operating in close proximity to humans (Feng et al., 2018). Moreover, the compatibility of solid electrolytes with lithium-metal anodes promises a step change in gravimetric energy density, potentially exceeding 400 Wh kg^-1 at the cell level (Manthiram, 2017; Randau et al., 2020). Equally compelling is the geometric versatility of SSBs: thin-film and flexible configurations enable conformal integration into robotic structures, a capability difficult to achieve with conventional pouch or cylindrical cells. Closely related anode-free architectures, which dispense with the dedicated anode foil and rely on in-situ lithium plating onto a bare current collector, push this energy-density frontier even further and remain an active focus of solid-state battery research relevant to volume- and mass-constrained robotic platforms (Sun et al., 2025).

Despite the growing body of literature on SSB materials and cell engineering, the discourse has been overwhelmingly framed around electric vehicles (EVs) and consumer electronics. This Perspective aims to bridge that gap. We argue that the convergence of solid-state battery technology and robotics represents not merely an incremental improvement in power sourcing, but a fundamental enabler of capabilities that are presently inaccessible.

2 Unique power requirements of modern robots

Safety in Human-Proximate Environments. The proliferation of collaborative robots (cobots), service robots, and wearable exoskeletons has brought batteries into direct physical contact with humans. A thermal runaway event in a conventional LIB—triggered by mechanical damage, internal short circuits, or thermal abuse—can result in temperatures exceeding 800 °C and the release of toxic gases (Feng et al., 2018; Wang et al., 2012). For robots operating in homes, hospitals, and public spaces, this risk profile is unacceptable. Regulatory frameworks, including ISO 13482 for personal care robots, increasingly mandate stringent safety requirements for onboard energy storage that conventional LIBs struggle to meet (International Organization for Standardization, 2014).

Energy Density and Operational Endurance. Untethered operation remains a defining challenge in mobile robotics. Current LIB-powered platforms typically achieve 1–4 h of continuous operation before requiring recharging—a limitation that severely restricts practical deployment (Bonnen Battery, 2024). The weight fraction allocated to batteries in mobile robots ranges from 20% to 40% of total system mass, creating a direct trade-off between energy capacity and payload. While ongoing progress in high-capacity silicon anode design and electrode engineering—encompassing volume-expansion management, functional binders, dry-electrode processing, and prelithiation strategies—is narrowing the energy-density gap within the conventional LIB paradigm (Kim et al., 2026), the form-factor rigidity and flammability constraints discussed above remain fundamentally unresolved by anode-side improvements alone, motivating the SSB-centric perspective developed here.

Form Factor Flexibility and Structural Integration. Unlike EVs, where battery packs occupy dedicated compartments, robots benefit enormously from distributed and conformal energy storage. Soft robots, in particular, require deformable power sources that can accommodate large strains without performance degradation. The concept of structural batteries—where the energy storage medium simultaneously serves as a load-bearing component—could fundamentally alter robotic design by eliminating the mass penalty associated with dedicated battery housings (Asp et al., 2021).

Power Density and Dynamic Loading. Robotic actuation demands are characterized by intermittent, high-current pulses rather than the sustained discharge profiles typical of EV driving. A legged robot, for example, may require burst currents exceeding 10C during jumping or rapid locomotion, interspersed with periods of minimal draw during static postures.

Environmental Resilience. Robots destined for field, industrial, or extraterrestrial deployment face temperature extremes (−40 °C–80 °C), mechanical shock, and vibration loads that far exceed the operating envelopes of most commercial LIBs. The temperature-dependent ionic conductivity of liquid electrolytes, coupled with the risk of electrolyte freezing or decomposition, presents fundamental limitations that solid-state alternatives may circumvent.

3 Solid-state battery advantages for robotic applications

Having established the unique power requirements of robotic systems, we now examine how the intrinsic properties of SSBs align with these demands (Figures 2, 3).

Intrinsic Safety Through Non-Flammable Electrolytes. The most compelling advantage of SSBs for robotics is the elimination of flammable liquid electrolytes. Inorganic solid electrolytes—whether oxide-based (e.g., Li7La3Zr2O12, LLZO) or sulfide-based (e.g., Li6PS5Cl)—are inherently non-flammable and do not generate combustible gases upon failure (Feng et al., 2018; Janek and Zeier, 2016).

Extended Temperature Operation. Solid electrolytes maintain ionic conductivity across temperature ranges that cause liquid electrolytes to freeze, boil, or decompose. Sulfide-based electrolytes exhibit room-temperature ionic conductivities exceeding 10^–3 S cm^-1 and retain functional performance at subzero temperatures (Kato et al., 2016). Oxide garnets demonstrate exceptional thermal stability up to 300 °C (Janek and Zeier, 2016).

Bipolar Stacking and Volumetric Efficiency. The absence of a liquid electrolyte enables bipolar cell architectures, achieving voltage multiplication within a single stack. For volume-constrained robotic platforms, the resulting improvement in volumetric energy density (potentially 30%–50% over conventional designs) represents a transformative advantage (Randau et al., 2020).

Thin-Film, Flexible, and Conformal Designs. Solid electrolyte thin films can be deposited by sputtering, atomic layer deposition (ALD), or solution processing, enabling battery architectures with thicknesses on the order of micrometers (Janek and Zeier, 2016).

Structural Battery Potential. Carbon fiber electrodes combined with solid polymer electrolyte matrices have demonstrated specific energies of 24 Wh kg^-1 with elastic moduli exceeding 25 GPa (Asp et al., 2021). While below thresholds for primary structural members—a typical robotic load-bearing chassis demands ≥150 Wh kg^-1 combined with ≥40 GPa modulus to substitute for current aluminum or CFRP frames without payload penalty—the mass savings from eliminating dedicated battery housings already yield net system-level benefits at present-day performance, and projected gains toward ∼75 Wh kg^-1 and ∼75 GPa would close roughly half of this gap. On this basis we characterize fully load-bearing structural SSBs—i.e., as substitutes for primary chassis members—as a longer-horizon (2030s and beyond) opportunity rather than a near-term commercial solution. In the near term (2025–2028), the realistic deployment path is parasitic-mass reduction by integrating thin SSB layers into secondary structural elements such as enclosure covers, body panels, and non-load-critical brackets; this captures part of the housing-elimination benefit without exposing the cell to the strain and impact envelope of a primary load path.

Extended Cycle Life and Total Cost of Ownership. As demonstrated in Figure 2B, the high cycling frequency inherent to hot-swap robotic operations makes cycle life a dominant factor in total cost of ownership. If SSBs can deliver 3,000–5,000 cycles—as projected for some sulfide and oxide systems (Zhang et al., 2018)—the number of battery replacements over a robot’s service life could be halved, reducing both cost and the environmental burden of battery production and disposal—a sustainability advantage that complements parallel innovations in next-generation cathode chemistries (Kakarla et al., 2025). A clear distinction must be drawn between laboratory and commercially validated cycle life. The 3,000–5,000-cycle figure refers to small-format laboratory cells—typically coin or sub-Ah pouch cells—cycled at modest C-rates (0.1–1C) under tightly controlled temperature, pressure, and atmosphere (Zhang et al., 2018). Commercially relevant multi-Ah cells assembled under manufacturing tolerances and cycled under the broader thermal, current, and mechanical envelope expected in robotic deployment currently report 500–1,500 cycles to 80% retention (Randau et al., 2020). Closing this lab-to-pack gap is one of the central engineering tasks the field must accomplish before the cumulative-cycling economics outlined here can be realized in deployed robotic fleets.

4 Current state of solid-state electrolyte technologies

The landscape of solid electrolyte materials is diverse—spanning oxide, sulfide, polymer, and emerging halide systems—and their suitability for robotic applications varies considerably (Table 1; Figure 4) (Janek and Zeier, 2016; Randau et al., 2020; Tan et al., 2025; Zhang et al., 2018).

4.1 Oxide-based solid electrolytes

Garnet-type LLZO and NASICON-type LATP (Li1+xAlxTi2−x (PO4)3) represent the most thermally and chemically stable solid electrolytes. LLZO offers ionic conductivities of approximately 10⁻⁴–10^–3 S cm^-1 at room temperature (Janek and Zeier, 2016; Zhang et al., 2018). However, the inherent brittleness of oxide ceramics poses a significant challenge for robotic applications involving mechanical shock and vibration.

4.2 Sulfide-based solid electrolytes

Argyrodite (Li₆PS₅Cl) and Li₃PS₄-based glass-ceramics exhibit the highest room-temperature ionic conductivities, reaching 10^–2 S cm^-1 (Kato et al., 2016). Their relatively low Young’s modulus enables cold-pressing fabrication. However, sulfide electrolytes generate toxic H₂S upon moisture exposure, necessitating hermetic packaging. Safe deployment of sulfide-based SSBs in human-proximate, mechanically perturbed robotic systems therefore requires a defence-in-depth approach: (i) hermetically sealed metal-laminated cell enclosures with redundant gasketing rated for the shock and vibration environment of mobile platforms; (ii) cell-level moisture-getter inclusion and inert internal headspace to retard H2S evolution even after partial enclosure breach; and (iii) onboard H2S sensing coupled with rapid pack isolation and shutdown protocols, ideally certified against ISO 13482 personal-care-robot safety requirements (International Organization for Standardization, 2014). In parallel, oxysulfide and halide-substituted compositions have been reported to markedly suppress H2S evolution while retaining the cold-pressability that motivates sulfide-class electrolytes in the first place, offering a promising pathway toward intrinsically safer sulfide-class systems for human-shared robotic operation (Tan et al., 2025).

4.3 Polymer-based solid electrolytes

PEO-based electrolytes achieve ionic conductivities of ∼10^–4 S cm^-1 at 60 °C–80 °C but suffer from poor room-temperature conductivity (∼10^–6 S cm^-1) (Janek and Zeier, 2016). Single-ion conducting polymers represent promising directions for achieving room-temperature performance while retaining mechanical flexibility.

4.4 Comparative assessment

TABLE 1. Comparison of solid electrolyte classes for robotic applications.

5 Remaining challenges and robotics-specific hurdles

Interface Resistance and Dendrite Growth. The solid–solid interface remains the most critical limitation of SSB technology. Lithium dendrite propagation has been observed in both oxide and sulfide systems under high current densities (>1 mA cm^-2) (Kasemchainan et al., 2019; Krauskopf et al., 2020). Strategies including interlayer engineering and anode-free architectures have shown promise but remain far from commercialization (Sun et al., 2025).

Mechanical Durability Under Dynamic Loads. Repetitive impact loading, sustained vibration, and large-strain deformation can induce crack propagation in ceramic electrolytes and delamination at interfaces. Mechanically robust SSB architectures—including interfacially reinforced crosslinked binders that maintain structural integrity in silicon-based electrodes for all-solid-state cells (Lee et al., 2026)—are a prerequisite for robotic deployment. It is important to acknowledge that, at present, SSB prototypes still trail state-of-the-art LIBs in sustained high-rate power capability. The best-reported sulfide-based SSB cells deliver continuous discharge at 2–3C with capacity retention comparable to LIBs (Kato et al., 2016), but >5C burst capability—routinely achieved by high-power LIB chemistries that already power dynamic robotic platforms—remains a target rather than a demonstrated capability in cells of practical (>10 Ah) format (Randau et al., 2020). Interfacial resistance under dynamic mechanical loading compounds this limitation: loss of solid–solid contact during impact, vibration, or repeated bending can raise the interfacial impedance by an order of magnitude and is currently a leading cause of capacity fade in early SSB pack prototypes (Krauskopf et al., 2020). Closing the high-rate and dynamic-load gap with incumbent LIB technology—particularly for legged and humanoid platforms whose actuation profile is dominated by burst currents—is therefore a precondition for direct replacement, even where the safety and cycle-life arguments are already compelling.

Scalable Manufacturing and Cost. Current SSB costs remain 5–10× higher than conventional LIBs (Randau et al., 2020). However, the total-cost-of-ownership analysis presented earlier suggests that the cost premium may be offset by the reduced replacement frequency enabled by SSBs’ superior cycle life.

Fast Charging for Field Deployment. Achieving 3C–5C charging rates without capacity fade or dendrite formation is a critical milestone for field robots (Kasemchainan et al., 2019). It is sometimes argued that emerging high-power wireless or opportunistic charging could obviate the hot-swap paradigm and, by extension, the cycle-life premium that motivates SSBs. In practice, however, the dominant deployments of service robots in logistics, hospitality, and inspection are throughput-constrained, and wireless charging at present-day kW-class power levels still requires the robot to dwell at a pad for tens of minutes per cycle—an unacceptable duty-cycle penalty for high-utilization fleets. Hot-swap therefore remains the operationally dominant mode for the foreseeable future, and the cumulative-cycling argument developed in this Perspective applies regardless of whether replenishment is achieved by physical pack exchange or by ultra-fast contact charging.

6 Future outlook: convergence of SSB and robotics

Despite these challenges, several emerging trends suggest that the integration of SSBs into robotic systems is not only feasible but may occur sooner than many anticipate.

Soft Robots and Flexible SSBs. Polymer-based solid electrolytes accommodating strains of 10%–50% offer a natural power solution for soft robots. Recent laboratory demonstrations of stretchable solid-state cells have shown encouraging mechanical and electrochemical retention under repeated deformation, though reported specific energies remain modest and the technology is at an early stage requiring validation at scale.

Structural Batteries. CFRP structural batteries have demonstrated feasibility in aerospace contexts (Asp et al., 2021). For robotic exoskeletons, the chassis itself could serve as the battery.

AI/ML-Accelerated Discovery. The vast compositional space of solid electrolytes cannot be efficiently explored through traditional experimentation alone. Machine learning models trained on high-throughput computational datasets (e.g., the Materials Project) have demonstrated the ability to predict ionic conductivity and mechanical properties with sufficient accuracy to guide targeted experimental synthesis (Sendek et al., 2017). Beyond first-generation screening, recent workflows combine extended electrochemical fingerprints (e-ECFP) and deep neural networks with post hoc interpretability tools such as SHAP, allowing the explicit attribution of predicted ionic conductivity to local structural motifs and elemental substitutions. For robotics-relevant SSBs, such interpretable surrogates are particularly valuable because the design objective is multi-criterion—conductivity, mechanical compliance, air stability, and cycle life simultaneously—rather than the single-property optimization typical of EV-oriented screens. Concrete robotics-relevant demonstrations are beginning to emerge. Machine-learning-guided screening has accelerated discovery of polymer electrolyte compositions that simultaneously achieve room-temperature conductivity above 10^–4 S cm^-1 and fracture strain above 50%—a combination directly relevant to soft and wearable robotic end-effectors—and has supported the design of halide-class electrolytes with improved ambient-air stability, relaxing glovebox requirements during cell assembly and lowering the manufacturing cost barrier (Tan et al., 2025). Active-learning loops that couple high-throughput synthesis with mechanical impact and bend-cycle testing are also being explored to target shock-resistant electrolyte–electrode interfaces, an objective with no direct EV analogue but with first-order relevance to mobile and legged robotic platforms.

Projected Roadmap (Figure 5). Near-term (2025–2028): thin-film SSBs for micro-robots. Mid-term (2028–2032): sulfide SSB packs for service robots (>350 Wh kg^-1). Long-term (2032–2035+): fully integrated structural SSBs in commercial platforms. We acknowledge that this timeline is aggressive given current SSB manufacturing cost and scalability challenges; its realization is contingent on four key technological milestones. (i) Wet-processed, roll-to-roll-compatible sulfide or polymer electrolyte films reaching <30 µm thickness with defect densities below the threshold at which dendrite-initiating pinholes form. (ii) Pack-level energy densities ≥350 Wh kg^-1 demonstrated in ≥10 Ah cells with cycle life ≥2,000 at relevant C-rates and across the −10 to +50 °C operating window of field robots. (iii) Cost reduction to within ∼2× of present LIB pack costs, achievable only through electrolyte raw-material price reduction and high-throughput dry- or solvent-minimized electrode coating. (iv) Standardization of safety, swap-interface, and communication protocols across robot OEMs to support hot-swap interoperability. Delays in any one of these milestones will shift the near-, mid-, and long-term horizons correspondingly to the right, and the timeline should therefore be read as conditional rather than predictive.

7 Conclusion and perspective

Solid-state batteries and robotics are two fields undergoing rapid, independent evolution. This Perspective has argued that their convergence is not only natural but necessary—and that the robotics community offers a uniquely demanding yet rewarding application domain for SSB technology.

The key insights may be summarized as follows. First, robotic power requirements align remarkably well with SSB properties. Second, the cumulative battery demand of a single commercial robot over its service life rivals that of a passenger EV, making cycle life and safety improvements disproportionately valuable in this sector. Third, each solid electrolyte class offers distinct advantages for specific robotic platforms, suggesting a diversified development approach that may extend beyond lithium chemistry to emerging sodium-based solid-state systems (Lee et al., 2025). Fourth, the remaining challenges are addressable but require deliberate attention to robotics-specific requirements.

We call upon the battery research community to expand its application horizon beyond electric vehicles and to engage with the robotics community in defining the performance targets, testing protocols, and form factors that will govern the next-generation of mobile power systems. The era of SSB-powered robotics is not a distant aspiration; it is an engineering challenge whose foundational elements are already in place.

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Footnotes

Edited by: Muhammad Kashif Majeed, National University of Sciences and Technology, Pakistan

Reviewed by: Ghulam Hussain, National University of Sciences and Technology, Pakistan