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Abstract Ambient-temperature sodium-sulfur (Na-S) batteries are potential attractive alternatives to lithium-ion batteries owing to their high theoretical specific energy of 1,274 Wh kg−1 based on the mass of Na2S and abundant sulfur resources. However, their practical viability is impeded by sodium polysulfide shuttling. Here, we report an intercalation-conversion hybrid positive electrode material by coupling the intercalation-type catalyst, MoTe2, with the conversion-type active material, sulfur. In addition, MoTe2 nanosheets vertically grown on graphene flakes offer abundant active catalytic sites, further boosting the catalytic activity for sulfur redox. When used as a composite positive electrode and assembled in a coin cell with excess Na, a discharge capacity of 1,081 mA h gs −1 based on the mass of S with a capacity fade rate of 0.05% per cycle over 350 cycles at 0.1 C rate in a voltage range of 0.8 to 2.8 V is realized under a high sulfur loading of 3.5 mg cm−2 and a lean electrolyte condition with an electrolyte-to-sulfur ratio of 7 μL mg−1. A fundamental understanding of the electrocatalysis of MoTe2 is further revealed by in-situ synchrotron-based operando X-ray diffraction and ex-situ time-of-flight secondary ion mass spectrometry.

Recent advances in machine learning (ML) are expediting materials discovery and design. One significant challenge facing ML for materials is the expansive combinatorial space of potential materials formed by diverse constituents and their flexible configurations. This complexity is particularly evident in molecular mixtures, a frequently explored space for materials, such as battery electrolytes. Owing to the complex structures of molecules and the sequence-independent nature of mixtures, conventional ML methods have difficulties in modeling such systems. Here, we present MolSets, a specialized ML model for molecular mixtures, to overcome the difficulties. Representing individual molecules as graphs and their mixture as a set, MolSets leverages a graph neural network and the deep sets architecture to extract information at the molecular level and aggregate it at the mixture level, thus addressing local complexity while retaining global flexibility. We demonstrate the efficacy of MolSets in predicting the conductivity of lithium battery electrolytes and highlight its benefits in the virtual screening of the combinatorial chemical space.

Abstract Since the very first patent on poly(3,4-ethylenedioxythiophene) (PEDOT) that was filed in 1988, this polymer has been widely utilized and has achieved great success owing to its high electrical conductivity and excellent stability. The application of the conducting polymer, PEDOT, in renewable energy devices, especially rechargeable batteries, is attracting increasing attention due to its potential to solve the energy and climate crisis. In this review, we summarize the research over the past few decades directed toward the application of PEDOT in rechargeable batteries aimed at improving their electrochemical performance. We focus on PEDOT synthesized via oxidative chemical vapor deposition (oCVD), a relatively new process known for its ability to grow conducting polymer thin films with uniform, pinhole-free properties, and controllable thickness and conformality. For a comparison purpose, PEDOT synthesized via solution-based methods is also briefly summarized. Finally, future research directions for applying oCVD PEDOT in rechargeable batteries are discussed. Introduction PEDOT Synthesis Methods Application of oCVD PEDOT in Rechargeable Batteries Applications of Solution-Based PEDOT in Rechargeable Batteries Conclusions and Outlook

Enhancing the reversibility of Li is crucial for extending the cycle life of Li‐limited anode‐free lithium–sulfur (Li–S) batteries. Incorporating tellurium (Te) in the system has proven to be highly effective by its reaction with polysulfides and forming a passivating interfacial layer on Li surface, which reduces the Li‐ion diffusion barrier. However, due to the poor utilization of Te, a significant amount of Te is required to improve cell cycling performance. To address this, nanowire‐structured Te (TeNW) is synthesized via a hydrothermal method and applied to Li2S‐based anode‐free cells to minimize the Te content in the system while extending the cell cycle life. Coating TeNW onto the separator greatly enhances Te utilization and demonstrates a significant cycle life improvement (38% retention over 300 cycles) with only 4 wt% TeNW content relative to the active material. The versatility of TeNW is further demonstrated by utilizing them with carbon nanotubes as the anode substrate. The exceptional performance of TeNW is attributed to the high‐surface‐area nanostructure and excellent conductive network, facilitating efficient electron transfer during cell cycling. These advantageous properties position TeNW as a promising material to enhance the cycle life of Li‐limited Li–S batteries.

Abstract Real‐time onboard state monitoring and estimation of a battery over its lifetime is indispensable for the safe and durable operation of battery‐powered devices. In this study, a methodology to predict the entire constant‐current cycling curve with limited input information that can be collected in a short period of time is developed. A total of 10 066 charge curves of LiNiO2‐based batteries at a constant C‐rate are collected. With the combination of a feature extraction step and a multiple linear regression step, the method can accurately predict an entire battery charge curve with an error of < 2% using only 10% of the charge curve as the input information. The method is further validated across other battery chemistries (LiCoO2‐based) using open‐access datasets. The prediction error of the charge curves for the LiCoO2‐based battery is around 2% with only 5% of the charge curve as the input information, indicating the generalization of the developed methodology for predicting battery cycling curves. The developed method paves the way for fast onboard health status monitoring and estimation for batteries during practical applications.

Development of single‐crystal sodium layered oxide materials has garnered interest in recent years due to the success of analogous materials for lithium‐ion batteries. Methods utilizing single crystal precursors of transition‐metal spinel materials with the form TaMbO4 (T, M = Fe, Mn, Ni, Ti, Al, etc…, and a + b = 3) have been shown to yield materials that suppress intergranular cracking, but morphological control of sodium layered oxides has not been demonstrated with this method. Herein, tunable morphology of NaNi1/2Mn1/2O2 is demonstrated with materials that achieve 130 mA h g−1 at C/5 rate, with capacity retention ranging from 16% to 71% after 200 cycles depending on the morphology. Cycling with a localized high concentration electrolyte (LHCE) controls the influence of surface reactivity and underscores the critical role of the surface in capacity degradation. The impact that transition‐metal chemistry has on the tunability of particle morphology is explored, with the growth kinetics of the terminal and intermediate phases during calcination of the sodium layered oxide compositions having the largest effect on tunability from the single‐crystal templates. By understanding the factors that determine tunability, this work can be extended to offer morphological control without coprecipitation for sodium layered oxides broadly. [ABSTRACT FROM AUTHOR]

Low ionic migration and compromised interfacial stability pose challenges for low‐temperature batteries. In this work, we discovered that even with the state‐of‐the‐art localized high‐concentration electrolytes (LHCEs), uncontrolled Na electrodeposition occurs with a huge overpotential of >1.2 V at −20 °C, leading to cell failure within tens of hours. To address this, we introduce a new electrolyte category that incorporates an ionic liquid as a key solvation species. Diverging from traditional LHCEs, the IL‐tailored LHCE facilitates an anion–solvent‐molecules exchange within the solvation sheath between Na+ and organic cations at low temperatures. This behavior reduces solvation cluster size and strengthens Na+–anion coordination, which proves instrumental in enabling fast ionic dynamics in both the bulk liquid and at the interface. Therefore, durable Na electrodeposition and shuttle‐free, 0.5 Ah sodium–sulfur pouch cells are achieved at −20 °C, for the first time, surpassing the limitations of typical LHCEs. This tailoring strategy opens a new design direction for advanced batteries operating in fast‐charge and wide‐temperature scenarios. [ABSTRACT FROM AUTHOR]

Self‐powered untethered robots that can meander unrestrictedly, squeeze into small spaces, and operate in diverse harsh environments have received immense attention in recent years. As there is not a universal solution that can be applied to power robots with diverse forms, service functions, and a broad size range from nanometers to meters, the design, fabrication, and implementation of power systems with a suitable weight, desired power and operation duration, and adaptiveness to confined spaces and operation conditions represent one of the greatest challenges in robotic research. Herein, an overview of recent progress and challenges in developing the next‐generation energy harvesting and storage technologies is provided, including direct energy harvesting, energy storage and conversion, and wireless energy transmission for robots across all scales.

Lithium-sulfur (Li-S) batteries have undergone a dramatic transition in the last two decades. Research has evolved from tackling more fundamental challenges associated with the chemistry of sulfur, such as the polysulfide shuttle effect and the low conductivity of sulfur, via cathode engineering to solving the technical challenges associated with making practical high-energy batteries, such as lowering the electrolyte amount and stabilizing the Li-metal anode. This level of technology readiness has even encouraged several companies to seriously consider the Li-S technology viable for commercialization. With the view that both academia and industry are closer to the pursuit of developing practical Li-S cells for consumer use, we highlight in this commentary some avenues for solving both the remaining technical challenges as well as scale-up and manufacturing challenges.

Lithium-metal batteries (LMBs) are considered as one of the most promising energy storage devices due to the high energy density and low reduction potential of the Li-metal anode. However, the growth of lithium dendrites results in accumulated dead Li and safety issues, limiting the practical application of LMBs. LiNO3 is a well-known additive in lithium–sulfur batteries to regulate the solid–electrolyte interphase (SEI), effectively suppressing the redox shuttle of polysulfides. Recently, other nitrates have been investigated in various electrolyte and battery systems, yielding improved SEI stability and cycling performance. In this review, we provide an overview of various nitrates, including LiNO3 for lithium batteries, focusing on their mechanisms and performance. We first discuss the effect of nitrate anions on SEI formation, as well as the cathode–electrolyte interphase ​(CEI). The solvation behavior regulated by nitrates is also extensively explored. Some strategies to improve the solubility of LiNO3 in ester-based electrolytes are then summarized, followed by a discussion of recent progress in the application of nitrates in different systems. Finally, further research directions are presented, along with challenges. This review provides a comprehensive understanding of nitrates and affords new and interesting ideas for the design of better electrolytes and battery systems.