Flexible cathode: In this work, molybdenum-doped α-MnO2 was grown on carbon cloth to prepare CC@MMO flexible cathodes. The pillaring effect of Mo stabilized the lattice structure of MnO2 and reduced the migration energy barrier of zinc ions. Ultimately, the CC@MMO electrode exhibited fast electrochemical reaction kinetics as well as excellent flexibility and stability.

Microstructure-resolved simulation: Composite cathode design is critical for a high performance of all-solid-state batteries. This study aims to reveal the induced limitations of the cathode microstructure on electrochemical cell performance through structure-resolved simulations. By correlating structural properties and cell performance, promising design strategies are identified. Special focus is set on the influence of grain boundaries.

Effective ionic conductivity: Optimizing the effective ionic conductivity in solid-state-batteries is crucial to achieve the desired performance and take full advantage of high-capacity solid electrolytes. This work demonstrates that increasing effective ionic conductivity improves the accessible capacity in a Si/C based solid-state-anode with constant effective electronic conductivity.

Silaborane-based electrolytes are investigated for CIBs using DFT and AIMD computations. DFT unveils higher stability of SiB11H11R− anions with −NCS and −CF3 substituents. AIMD analysis reveals that calcium salts based on −NCS and −CF3 substituted silaboranes decompose on Ca anode while the −CH3 substituted silaborane remains unaffected suggesting that Ca(SiB11H11CH3)2 is a promising electrolyte for CIBs.

3D printing holds great potential for micro-electrochemical energy storage devices (MEESDs). This review summarizes the fundamentals of MEESDs and recent advancements in 3D printing techniques for MEESDs including micro-supercapacitors (MSCs), micro-batteries (MBs), and metal-ion hybrid micro-supercapacitors (MIHMSCs).

Lithium-ion capacitors (LICs) represent promising high power energy storage devices, most commonly composed of a Li-ion intercalation anode (e.g., graphite or hard carbon), a supercapacitor activated carbon (AC) cathode, and an electrolyte with 1 M LiPF6 in carbonate solvents. Here, we report on the feasibility of replacing LiPF6 with the novel salt LiFSI for use with AC electrodes. Based on voltage hold measurements in a half-cell setup, good long-term stability is achieved with an upper cut-off voltage of 3.95 V vs. Li/Li+, potentially enabling cell voltages of ~3.8 V when combined with graphite anodes (operating at ~0.1 V vs. Li/Li+) in LIC full cells. The systematic comparison of cyclic voltammetry, leakage current analysis, and capacity retention upon voltage hold highlights the importance of the latter method to provide a realistic assessment of the electrochemical stability window of LiFSI on AC. The morphological and surface-chemical post-mortem analysis of AC electrodes used with LiFSI revealed that the oxidation of the FSI anion, as evidenced by the presence of new S 2p and N 1s features in the XPS spectra, and an increasing amount of oxygenated species on the AC were the main processes causing capacity fade at positive polarization.

Functional electrolyte additives can improve the stability and safety of high voltage lithium-ion batteries. A mixture of fluoroethylene carbonate (FEC) and succinonitrile (SN) in a carbonate-based electrolyte improved the cycling stability and electrochemical stability window of a LMNO−Li device. The FEC+SN electrolyte also exhibited better thermal stability using operando accelerating rate calorimetry (ARC) by virtue of its reduced heat generation.

Towards chloride-free aluminum battery electrolytes: This report discusses the development of a chloride-free organic electrolyte from which reversible aluminum plating can be carried out at room temperature, characterization of the aluminum deposits and insight into electrolyte speciation using both experimental and computational techniques.

Similar but different: The decomposition of electrolyte components at the metal anode surface is of great importance for the formation of the solid electrolyte interface. AIMD simulations shine light on the many similarities between the well-established lithium systems with the emerging sodium and potassium systems while highlighting lithium's higher tendency to form organic structures via polymerization reactions.

Towards printable batteries. This review first introduces the key elements of the customizable battery and the advantages of 3D printing. Then, the common 3D printing technologies and their application progress in customizing battery interior pores, component architecture and interface, as well as deformability and appearance are explained. Finally, future challenges and solutions are proposed.

Are supercapacitors always stable? While supercapacitors have a reputation for stability and long lifetimes, here we demonstrate that a commercially available Li-ion pseudocapacitor system can indeed degrade prematurely and rapidly under moderate cycling conditions. Teardown analysis and multi-length scale characterization, using techniques such as X-ray computed tomography and Raman spectroscopy, shows that this is due to the swift and irreversible degradation of a widely used electrode material.

The degradation process: The effects of electrochemical ageing of Si−C based electrodes were interrogated by determining the coulombic efficiency and electrochemical impedance spectroscopy after cycling. The macroscopic analysis generated inconclusive interpretations for the cycled samples. Local electrochemical measurements by scanning electrochemical microscopy (SECM) were employed as a complementary technique to evaluate the protecting properties of the solid electrolyte interphase (SEI). SECM maps revealed the formation of a protective SEI after few cycles with increasing inhomogeneities with the number of cycles.

“We observed less heat generation at a low C-rate in the case of G4 and better electrochemical performance. In G4 solvent stable cycling and fewer self-discharge phenomena are observed, however, the activation process needs more cycles to achieve the required capacity…” Learn more about the story behind the research featured on the front cover in this issue's Cover Profile. Read the corresponding Research Article on 10.1002/batt.202300137.

Redox-active oligomer flow cell performance: We synthesized a series of redox-active oligomers and investigated their reaction kinetics and mass transport using electroanalytical methods and symmetric cell testing. We find that characteristics measured in the flow cell closely mirror ex situ trends in reversibility and diffusivity, validating and extending upon previously-developed property-performance relationships.

Towards Scalable production: Electrodes based on a porous carbon current collector outperforms conventional electrodes on aluminum foil when the loading is very high (e. g., >8 mAh/cm2), likely due to better adhesion. Electrodes with loadings up to 12 mAh/cm2 could be prepared via an infiltration process which was designed to be scalable.

The Cover Feature illustrates the function of GalvAnalyze, a new battery data analysis tool which automatically segments, organizes, and plots galvanostatic charge-discharge cycling data and produces common plots using an accessible graphical user interface. More information can be found in the Research Article by R. C. McNulty and L. Rier.

Microporous biomass carbon: The Enteromorpha-derived nitrogen-doped highly microporous carbon (HMCs) was prepared by carbonization and activation. Due to the high specific surface area, rich pore structure and nitrogen doping of HMCs, HMCs-3@S/SeS2 cathode exhibits excellent cycling stability and rate performance in aqueous Zn-chalcogen batteries.

The suitability of TEA-AlCl3 electrolyte for Al-graphite AIB is assessed by monitoring of electrode potentials during long-term cycling at 1 A g−1. While Al electrode potential decreases continuously allowing steady increase of graphite electrode potential and cell capacity, those of AIB in 1.5 Emi remain constant.

Besides discharge and electrochemical impedance spectroscopy, nonlinear frequency response analysis is implemented to investigate the ageing behaviour of different particle size distributions. Nonlinear frequency response analysis is useful for surface analysis, which offers additional information on the charge transfer kinetic and symmetry that cannot be assessed via a typical linear approach.

Electrolyte formation onsite: We focused on MgCl2, which reversibly self-generates a solid electrolyte during the lithiation process, as an anode material that can operate without a solid electrolyte incorporated into the electrode mixture. X-ray diffraction and X-ray absorption spectroscopy analyses showed that lithiation produced Mg and LiCl, which were recovered to MgCl2 by subsequent delithiation.