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Lithium‐sulfur (Li‐S) batteries hold immense promise as next‐generation energy storage due to their high theoretical energy density (2600 Wh kg⁻¹), low cost, and non‐toxic nature. However, practical implementation faces challenges, primarily from Li polysulfide (LiPS) shuttling within the cathode and Li dendrite growth at the anode. Optimized electrodes/electrolytes design effectively confines LiPS to the cathode, boosting cycling performance in coin cells to up to hundreds of cycles. Scaling up to larger pouch cells presents new obstacles, requiring further research for long‐term stability. A 1.45 Ah pouch cell, with optimized sulfur loading and electrolyte/sulfur ratio is developed, which delivers an energy density of 151 Wh kg⁻¹with 70% capacity retention up to 100 cycles. Targeting higher energy density (180 Wh kg⁻¹), the developed 1Ah pouch cell exhibits 68% capacity retention after 50 cycles. Morphological analysis reveals that pouch cell failure is primarily from Li metal powdering and resulting polarization, rather than LiPS shuttling. This occurs for continuous Li ion stripping/plating during cycling, leading to dendrite growth and formation of non‐reactive Li powder, especially under high currents. These issues increase ion diffusion resistance and reduce coulombic efficiency over time. Therefore, the study highlights the importance of a protected Li metal anode for achieving high‐energy‐dense batteries.

 

High energy density lithium–sulfur batteries (LSBs) are a potential replacement for lithium-ion batteries (LIBs). However, practical lifetimes are inhibited by lithium polysulfide (LiPS) shuttling. Concurrently, plastic waste accumulation worldwide threatens our ecosystems. Herein, a fast and facile strategy to upcycle polyethylene terephthalate (PET) waste into useful materials is investigated. Dilithium terephthalate (Li2TP) and dipotassium terephthalate (K2TP) salts were synthesized from waste soda bottles via microwave depolymerization and solution coated onto glass fiber paper (GFP) separators. Salt-functionalized separators with Li2TP@GFP and K2TP@GFP mitigated LiPS shuttling and improved electrochemical performance in cells. Pore analysis and density functional theory (DFT) calculations indicate the action mechanism is synergistic physical blocking of bulky LiPS anions in nanopores and diffusion inhibition via electrostatic interactions with abundant carboxylate groups. LSBs with K2TP@GFP separator showing highest LiPS affinity and smallest pore size demonstrated enhanced initial capacity as compared to non-modified GFP by 5.4% to 648 mAh g−1, and increased cycle 100 capacity by 23% to 551 mAh g−1. Overall, K2TP@GFP retained 85% of initial capacity after 100 cycles with an average capacity fading of 0.15% per cycle. By comparison, GFP retained only 73% of initial capacity after 100 cycles with 0.27% average capacity loss, demonstrating effective LiPS retention. 

Copper oxide nanostructures are widely used for various applications due to their unique optical and electrical properties. In this work, we demonstrate an atmospheric laser-induced oxidation technique for the fabrication of highly electrochemically active copper oxide hierarchical micro/nano structures on copper surfaces to achieve highly sensitive non-enzymatic glucose sensing performance. The effect of laser processing power on the composition, crystallinity, microstructure, wettability, and color of the laser-induced oxide on copper (LIO-Cu) surface was systematically studied using scanning electron microscopy (SEM), grazing incidence X-ray diffraction (GI-XRD), Raman spectroscopy, energy dispersive X-ray spectroscopy (EDX), EDX-mapping, water contact angle measurements, and optical microscopy. Results of these investigations showed a remarkable increase in copper oxide composition by increasing the laser processing power. The pore size distribution and surface area of the pristine and LIO-Cu sample estimated by N 2 adsorption–desorption data showed a developed mesoporous LIO-Cu structure. The size of the generated nano-oxides, crystallinity, and electroactivity of the LIO-Cu were observed to be adjustable by the laser processing power. The electrocatalytic activity of LIO-Cu surfaces was studied by means of cyclic voltammetry (CV) within a potential window of −0.8 to +0.8 V and chronoamperometry in an applied optimized potential of +0.6 V, in 0.1 M NaOH solution and phosphate buffer solution (PBS), respectively. LIO-Cu surfaces with optimized laser processing powers exhibited a sensitivity of 6950 μA mM −1 cm −2 within a wide linear range from 0.01 to 5 mM, with exceptional specificity and response time (<3 seconds). The sensors also showed excellent response stability over a course of 50 days that was originated from the binder-free robust electroactive film fabricated directly onto the copper surface. The demonstrated one-step LIO processing onto commercial metal films, can potentially be applied for tuneable and scalable roll-to-roll fabrication of a wide range of high surface area metal oxide micro/nano structures for non-enzymatic biosensing and electrochemical applications. 

Prussian blue analogues (PBAs) cathodes can host diverse monovalent and multivalent metal ions due to their tunable structure. However, their electrochemical performance suffers from poor cycle life associated with chemo‐mechanical instabilities. This study investigates the driving forces behind chemo‐mechanical instabilities in Ni‐ and Mn‐based PBAs cathodes for K‐ion batteries by combining electrochemical analysis, digital image correlation, and spectroscopy techniques. Capacity retention in Ni‐based PBA is 96% whereas it is 91.5% for Mn‐based PBA after 100 cycles at C/5 rate. During charge, the potassium nickel hexacyanoferrate (KNHCF) electrode experiences a positive strain generation whereas the potassium manganese hexacyanoferrate (KMHCF) electrode undergoes initially positive strain generation followed by a reduction in strains at a higher state of charge. Overall, both cathodes undergo similar reversible electrochemical strains in each charge–discharge cycle. There is ~0.80% irreversible strain generation in both cathodes after 5 cycles. XPS studies indicated richer organic layer compounds in the cathode‐electrolyte interface (CEI) layer formed on KMHCF cathodes compared to the KNHCF ones. Faster capacity fades in Mn‐based PBA, compared to Ni‐based ones, is attributed to the formation of richer organic compounds in CEI layers, rather than mechanical deformations. Understanding the driving forces behind instabilities provides a guideline to develop material‐based strategies for better electrochemical performance.

 

Potassium‐ion batteries (KIBs) are considered more appropriate for grid‐scale storage than lithium‐ion batteries (LIBs) due to similar operating chemistry, abundant precursors, and compatibility with low‐cost graphite anodes. However, a larger ion reduces rate capabilities and exacerbates capacity fading from volumetric expansion. Herein, conductive polymer, poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), is substituted for standard insulating polyvinylidene fluoride (PVDF). Half‐cells using carbon black (CB) in continuously conductive PEDOT:PSS/CB binder outperforms PVDF/CB by mitigating electrically isolated “dead” graphite, improving 100 cycle capacity retention at C/10 from 63 to 80%. Enhanced electrical contact with PEDOT:PSS/CB also reduces ion impedance and improves rate capabilities. Without CB however, PEDOT:PSS binder performs poorly in electrochemical studies despite promising ex situ electronic conductivity. This discrepancy is mechanistically elucidated through identification of redox activity between PEDOT:PSS and K⁺which results in high impedances in the anode operating voltage window. Additionally, the impact of conducting binder on mechanical properties and thermal safety of the anode is investigated. Brittleness and poor wettability of PEDOT:PSS are identified as issues, but greater stability against reactive KC₈reduces overall heat generation. Binder substitution offers a promising means of mitigating issues with current KIB anodes regardless of active material, and the work herein addresses issues towards further improvement.

 

Ethylene and diethyl carbonates (EC : DEC) have been attractive solvents for Li‐ion electrolytes because these can exhibit a good ionic conductivity and stable electrochemical performance. However, in the contemporary K‐ion electrolytes, KPF₆presents a limited solubility of ∼0.6 M in EC : DEC (volume ratio 1 : 1), which restricts its performance. Here, the molecular basis for these distinct solvation behaviors is clarified by combining experimental attenuated total reflectance‐infrared spectroscopy and electrochemical impedance spectroscopy measurements with molecular dynamics simulations, revealing the distinct roles of EC and DEC solvents on the solubility, ionic conductivity, and solvation shell structures of KPF₆and LiPF₆salts in EC : DEC mixtures. In turn, these insights have enabled the formulation of a new K‐ion electrolyte with EC : DEC volume ratio of 1.5 that exhibits significantly increased KPF₆solubility (∼0.9 M) and ionic conductivity, reaching 13.99 mS cm⁻¹at 25 °C.

 

Since their commercialization by Sony in 1991, graphite anodes in combination with various cathodes have enabled the widespread success of lithium‐ion batteries (LIBs), providing over 10 billion rechargeable batteries to the global population. Next‐generation nonaqueous alkali metal‐ion batteries, namely sodium‐ion batteries (SIBs) and potassium‐ion batteries (PIBs), are projected to utilize intercalation‐based carbon anodes as well, due to their favorable electrochemical properties. While traditionally graphite anodes have dominated the market share of LIBs, other carbon materials have been investigated, including graphene, carbon nanotubes, and disordered carbons. The relationship between carbon material properties, electrochemical performance, and charge storage mechanisms is clarified for these alkali metal‐ion batteries, elucidating possible strategies for obtaining enhanced cycling stability, specific capacity, rate capability, and safety aspects. As a key component in determining cell performance, the solid electrolyte interphase layer is described in detail, particularly for its dependence on the carbon anode. Finally, battery safety at extreme temperatures is discussed, where carbon anodes are susceptible to dendrite formation, accelerated aging, and eventual thermal runaway. As society pushes toward higher energy density LIBs, this review aims to provide guidance toward the development of sustainable next‐generation SIBs and PIBs.