Solid-State and Sustainable Batteries

The acceleration of the global carbon neutrality agenda is driving the transformation of energy storage technologies. As a result, the battery field is undergoing a paradigm shift from singular performance advantage to synergistic development of multiple aspects of efficiency, safety, and environmental friendliness. This special issue of the journal Advanced Sustainable Systems focuses on solid-state and sustainable batteries, systematically demonstrating how synergistic interactions between material innovations, structural engineering, and system architecture are key to overcoming the existing technological constraints.

This special issue contains 13 papers about the design and development of electrodes, electrolytes, and their interfaces in solid-state and sustainable lithium/sodium-ion (Li⁺/Na⁺) batteries, as well as wearable batteries. We would like to express our sincere thanks to all authors who have contributed to this special issue. A summary of all 13 accepted papers is provided as follows.

In terms of synergistic optimization of material systems, the fields of electrodes and electrolytes show a multifaceted innovation trend. For electrodes, Luo et al. (202300233) presented a novel Na₄MnCr(PO₄)₃/C@KB composite, which enhances rate capability and capacity retention through improved conductivity and electrolyte infiltration. Benefiting from an increase of electronic conductivity and an adequate infiltration of electrolyte by substantial pores existence in carbon layer, this novel Na₄MnCr(PO₄)₃/C@KB composite material exhibits improved rate capability of 61.2 mAh g⁻¹ at 2 C compared to 19.5 mAh g⁻¹ of Na₄MnCr(PO₄)₃/C and high reversible capacity of 88.0 mAh g⁻¹ at 1 C with 73% capacity retention after 100 cycles. Gong et al. reported one type of one-dimensional (1D) sulfur chain encapsulated in SWCNTs (S@SWCNTs), which was designed as the cathode for lithium-sulfur (Li–S) batteries (202300308). Experimental studies and density functional theory calculations reveal the suppressed shuttle effect and the accelerated sulfur reduction kinetics in S@SWCNTs cathodes with the spatial confinement effect of SWCNTs. Thus, the S@SWCNTs as the self-supporting cathodes can exhibit capacity retention of 94% after 100 cycles with a high sulfur loading of 5.84 mg cm⁻² and low E/S (electrolyte/sulfur) ratio of 4.3 µL mg⁻¹, promising for high energy-density batteries. Zhang and co-workers reported a Ru/Al dual doping strategy to enhance the cycling stability of LiCoO₂ under high-voltage operation by synergistically reconfiguring the electronic structure and stabilizing the lattice framework (202300325). Consequently, an initial capacity of 197 mAh g⁻¹ and 86% capacity retention after 100 cycles were achieved from 3.00 to 4.53 V vs Li⁺/Li.

For electrolytes, the design of physical isolation, lithium alloy, and bilayer electrolyte structure from Song and co-workers effectively solved the instability of hydride electrolytes in Li anode and high-voltage cathode (202400366). Zhang et al. (202400369) proposed the synergistic incorporation of a fast ionic conductor (LiBH₄) and a Lewis acid (Al₂O₃) into PEO-based composite electrolytes. The ionic conductivity of the PEO-based electrolyte is significantly improved by this synergistic effect of dual fillers and the growth of dendrites at the anode is effectively suppressed. Yang et al. (202400729) investigated the triggering mechanism of Li dendrite nucleation caused by the electronic conductivity of sulfide solid-state electrolytes. The article proposes a dual strategy of reducing the electronic conductivity of electrolytes while optimizing sulfur utilization in cathodes, offering a theoretical framework for the design of high-performance ASSLSBs. Jin and colleagues systematically summarized the progress of low-temperature Li metal batteries (202300285). The challenges and influences of low temperatures on Li metal batteries are concluded. Subsequently, the solutions to low-temperature Li metal batteries based on electrolyte engineering have been reviewed and discussed. The techniques for low-temperature characterizations are classified and discussed. Most importantly, the future development prospects of low-temperature Li metal batteries are proposed from sustainable perspectives.

Exciting reports highlight the crucial role of interface engineering in enhancing the energy density of solid-state and sustainable batteries. Xie et al. discussed the precise fabrication of a Li₃PO₄ interface layer using atomic layer deposition (ALD) technology in PEO-based all-solid-state batteries to suppress interfacial side reactions (202300392). Meanwhile, Zhang and co-workers employed hydride (Li(NH₃)_0.2BH₄) coating at room temperature to modify the garnet-based electrolyte LLZTO, effectively reducing interfacial contact resistance (202400428). This approach opens a new pathway for the preparation of high-performance solid-state electrolytes. Besides, Zhang and co-workers also reported a multifunctional crosslinked polymer interface (PAP) formed in situ on LiCoO₂ (LCO), creating a nanoscale conformal coating that suppresses deleterious side reactions with the electrolyte (202400519). Attributing to its anti-high-voltage characteristics and high Li⁺ conductivity, the PAP interface has excellent high-voltage stability and Li⁺ transport kinetics.

The special issue includes several valuable reviews exploring promising solid-state and sustainable batteries. Song et al. summarized the latest advancements in all-solid-state Li-S batteries highlighting key strategies such as the construction of three-dimensional (3D) ion/electron transport networks in sulfur cathodes and the design of interfacial buffer layer implementations (202400555). It proposes the use of lithium alloying and 3D electrode architectures to suppress dendrite growth, driving the development of high-energy-density ASSLSBs. In addition, Lv and colleagues (202300400) provided a comprehensive summary of proposed solutions aimed at addressing these problems, including electrolyte modification design, protective layer implementation, and structured Nametal anode development with the goal of achieving a stable interface, reversible Na plating/stripping processes, and prolonged cycling lifespan. Furthermore, this review discusses the underlying principles behind these strategies while offering insights into future research directions. Finally, the special issue also discusses the art of balancing stretchability and degradability in sustainable electronic wearable devices. Zhao et al. introduced a flexible, biodegradable battery with a kirigami-island-bridge structure, offering promising applications for medical and sustainable electronics (202400259).

This special issue not only outlines critical developments in energy storage technologies but also systematically elucidates the intrinsic correlation mechanisms spanning from nanoscale chemical reconstruction to macroscopic device performance optimization. It demonstrates the great potential of high-energy, high-safety, solid-state, and sustainable batteries for applications such as electric vehicles, grid-scale energy storage, and flexible electronics.

The authors declare no conflict of interest.