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[Display omitted] • A concept of multifunctional Li+ traffic controller is proposed. • The traffic controller can effectively regulate the distribution of Li+. • The traffic controller stabilizes the electrode-electrolyte interface. • The traffic controller layer enables ultra-low N/P ratio full cells. The performance of thin lithium metal anodes is affected due to issues that weaken the electrode-electrolyte interphase. In this work, a coating layer serving as a Li+ traffic controller based on hexadecyl trimethyl ammonium bis(trifluoromethanesulphonyl)imide ([CTA][TFSI]) and poly (vinylidene difluoride co-hexafluoropropylene) (P(VDF-HFP)) is used to stabilize the thin lithium metal interface. The CTA+ ions in the coating layer can effectively regulate the distribution of Li+ concentration to promote uniform deposition of lithium. The anion of [CTA][TFSI] can optimize solid electrolyte interphase (SEI) with inorganic-rich components, which improve the ionic conductivity and reaction kinetics. Furthermore, the flexible polymer skeleton can fortify the fragile SEI, facilitating the consistent operation of the battery. Due to these improvements, a thin Li metal anode (4 mAh cm−2) with a coating layer in a Li||Li symmetric cell demonstrates a lifespan of 600 h at 1 mA cm−2 and 1 mAh cm−2. Notably, full cells with an ultra-low negative electrode/positive electrode = 1 (N/P = 1) demonstrate a stable performance over 200 cycles and 90 cycles at 0.5C and 1C (1C = 170 mA g−1), respectively. [ABSTRACT FROM AUTHOR]

Exploiting thin Li metal anode is essential for high-energy-density battery, but is severely plagued by the poor processability of Li, as well as the uncontrollable Li plating/stripping behaviors and Li/electrolyte interface. Herein, a thickness/capacity-adjustable thin alloy-type Li/LiZn@Cu anode is fabricated for high-energy-density Li metal batteries. The as-formed lithophilic LiZn alloy in Li/LiZn@Cu anode can effectively regulate Li plating/stripping and stabilize the Li/electrolyte interface to deliver the hierarchical Li electrochemistry. Upon charging, the Li/LiZn@Cu anode firstly acts as Li source for homogeneous Li extraction. At the end of charging, the de-alloy of LiZn nanostructures further supplements the Li extraction, actually playing the Li compensation role in battery cycling. While upon discharging, the LiZn alloy forms just at the beginning, thereby regulating the following Li homogeneous deposition. The reversibility of such an interesting process is undoubtedly verified from the electrochemistry and in-situ XRD characterization. This work sheds light on the facile fabrication of practical Li metal anodes and useful Li compensation materials for high-energy-density Li metal batteries. Utilizing an ultra-thin Li anode with a thickness below 50 μm is crucial for enhancing the energy density of batteries. Here, the authors develop a finely tunable, thin alloy-based Li anode that features a hierarchical Li electrochemistry, enabling stable cycling and superior energy density in Li metal batteries. [ABSTRACT FROM AUTHOR]

Silicon is a desirable anode material for Li-ion batteries owing to its remarkable theoretical specific capacity of over 4000 mAh/g. Nevertheless, the poor cycling performance of pure Si electrodes caused by dramatic volume expansion has limited its practical application. To alleviate the adverse effects of Si expansion, we have synthesized anode materials of nano-Si particles trapped in a buffering space and outer carbon-based shells (Si@Void@C). The volume ratio of Si nanoparticle to void space could be adjusted accurately to approximately 1:3, which maintained the structural integrity of the as-designed nanoarchitecture during lithiation/delithiation and achieved a notable specific capacity of ~750 mAh/g for as-prepared half-cells. The yolk-shell nanostructure alleviates volumetric expansion on both material and electrode levels, which enhances the rate performance and cycling stability of the silicon-based anode. [ABSTRACT FROM AUTHOR]

Highlights • TiO x N y /C derived from MXene was fabricated for the first time. • TiO x N y /C is used as anode material of potassium-ion batteries for the first time. • The TiO x N y /C electrode displays good electrochemical performance. Abstract Titanium oxynitride nanoparticles/carbon composites (TiO x N y /C, x + y = 1) are successfully prepared from Ti 3 C 2 T x MXene and are first explored as anode material for potassium-ion batteries. The as-prepared titanium oxynitride nanoparticles/carbon composite exhibits impressive rate performance and high capacity. This work provides a new method for preparing MXene-derived TiO x N y /C and a promising anode material for potassium-ion batteries. [ABSTRACT FROM AUTHOR]