ACS Energy Letters 最新文献

Lithium metal batteries (LMBs) offer superior energy density and power capability but face challenges in cycle stability and safety. This study introduces a strategic approach to improving LMB cycle stability by optimizing charge/discharge rates. Our results show that slow charging (0.2C) and fast discharging (3C) significantly improve performance, with a multilayer LMB retaining over 80% capacity after 1000 cycles. Fast discharge rates promote lithium plating beneath the SEI layer, suppressing its growth and improving Coulombic efficiency, whereas slow discharge rates facilitate lithium plating above the SEI, leading to SEI accumulation. We propose a rational hypothesis linking SEI conductivity and cycling conditions and introduce an intermittent pulse discharge protocol to emulate electric vehicle applications, further improving the stability. These optimized cycling strategies enhance the LMB lifespan, utility, and safety, paving the way for broader market adoption in the years ahead.

Retired batteries are of great economic and environmental importance, which are indispensable considerations in the life cycle of lithium-ion batteries. However, existing methods for evaluating retired batteries are time- and resource-consuming, hindering efficient screening for later recycling or reuse. Herein, combining optical fiber sensors and interpretable machine learning (ML), we establish a data-driven framework for retired battery datasets with 265 cells of different chemistries (LiFePO₄/graphite, LiMn₂O₄/graphite) and achieve ultrafast state of health diagnosis within 3 min, offering mean absolute errors of 1.17% and 2.78%, respectively. The proposed data-driven framework identifies the salient regions in the time-resolved multivariable data and helps to uncover underlying thermodynamic/kinetic aging mechanisms. We also demonstrate the incorporated thermal information obtained via optical fibers complements voltage signals by improving prediction accuracy and antinoise ability. This work not only showcases the potential of battery sensing in retired battery diagnosis but also unlocks the unexplored synergy between sensing and interpretable ML for diverse battery applications.

The use of a lithium metal anode enables batteries with significantly higher energy density, but at the expense of the growth of lithium dendrites that trigger internal short circuits, induce safety risks, and reduce cycle stability. To address this challenge, here, we report the design of an aluminum fluoride nanowire membrane as a conversion interlayer to regulate lithium deposition for significantly more stable and safe lithium metal batteries. The interlayer generates a LiF-rich solid electrolyte interphase and alloy nanoparticles in contact with lithium to offer active sites guiding lithium nucleation, regulating lithium deposition, and increasing Coulombic efficiencies. With such an interlayer, lithium metal full cells show significantly improved stability compared to those with bare Cu, when paired with a LiFePO₄ or LiNi_0.8Co_0.1Mn_0.1O₂ cathode. Our results indicate that using an aluminum fluoride interlayer can be a promising strategy in realizing lithium metal batteries with high specific energy density.

Advanced bipolar membranes (BPMs) with low water-dissociation overpotential (η_wd) may enable new electrochemical technologies for electrolysis, fuel cells, acid–base synthesis, brine remediation, lithium-battery recycling, and cement production. However, these advanced BPMs have only been demonstrated in BPM water electrolysis (BPMWE) configurations where the BPM is under static compression by the porous-transport layers. It is important to study these BPMs in applications like electrodialysis where large degrees of static compression are not possible. We present a BPM electrodialysis (BPMED) platform to measure water-dissociation overpotential (η_wd) and compare BPMWE and BPMED systems. We show advanced BPMs with half the η_wd compared to commercial BPMs for BPMED while maintaining ∼90% current efficiency from 0.05–0.5 A cm^–2. The BPMED η_wd values are, however, about 0.2 V higher at 0.5 A cm^–2 than those for BPMWE. Regardless, these results show that BPMs developed and optimized in BPMWE applications are well-suited for next-generation high-current-density BPMED technologies.

Exploring a general method for constructing uniform heterostructures with sub-5 nm crystallites and dense interfaces is crucial yet challenging for advancing water electrocatalysis. Herein, a bottom-up cocrystallization strategy, involving in situ transformation of amorphous Ni–P through gas–solid reactions, is proposed to synthesize a series of nickel-based heterojunctions on carbon cloth (CC). Thereinto, interface-wealthy NiS₂-Ni₂P/CC with densely packed 3–4 nm crystallites demonstrates superb catalytic performance for both hydrogen and oxygen evolution. The electrolyzer merely requires cell voltages of 1.79 and 1.89 V to propel overall water splitting currents of 200 and 400 mA cm^–2, respectively, outperforming the vast majority of reported nickel-based heterojunctions. Theoretical calculations reveal that charge redistribution and electronic structure modulation optimize the hydrogen and oxygen evolution pathways at the NiS₂ and Ni₂P sides of the interfaces, respectively. Moreover, uniform hybridization with densely distributed heterointerfaces offers abundant active sites for electrocatalysis, pioneering an extendable approach for constructing advanced heterojunction catalysts for green hydrogen production.

Ion transport in two polymer electrolytes, poly(ethylene oxide) (PEO) and poly(pentyl malonate) (PPM), mixed with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is studied in the vicinity of the limiting current. The experimental measurements are in quantitative agreement with theoretical predictions based on the concentrated solution theory. The properties of two electrolytes are compared using a new plot wherein the length-normalized limiting current, i_limL, is plotted as a function of the length-normalized potential drop, Φ_lim/L, in symmetric cells with electrolyte thickness, L. We propose that electrolyte design should aim to obtain the largest values of i_limL and the smallest values of Φ_lim/L. Using this criterion, PPM/LiTFSI is a better polymer electrolyte than PEO/LiTFSI. We hope that PPM/LiTFSI will serve as a benchmark for developing next-generation polymer electrolytes.