Stable Cycling of Na Metal Batteries at Ultrahigh Capacity.

The development of sodium metal batteries has long been impeded by dendrite formation issues. State-of-the-art strategies, exemplified by sodiophilic hosting/seeding layers, have demonstrated great success in suppressing dendrite formation. However, addressing high-capacity applications (>10 mAh cm) remains a significant challenge.

Deciphering the Formation and Accumulation of Solid-Electrolyte Interphases in Na and K Carbonate-Based Batteries.

The continuous solid-electrolyte interphase (SEI) accumulation has been blamed for the rapid capacity loss of carbon anodes in Na and K ethylene carbonate (EC)/diethyl carbonate (DEC) electrolytes, but the understanding of the SEI composition and its formation chemistry remains incomplete. Here, we explain this SEI accumulation as the continuous production of organic species in solution-phase reactions. By comparing the NMR spectra of SEIs and model compounds we synthesized, alkali metal ethyl carbonate (MEC, M = Na or K), long-chain alkali metal ethylene carbonate (LCMEC, M = Na or K), and poly(ethylene oxide) (PEO) oligomers with ethyl carbonate ending groups are identified in Na and K SEIs.

Key Factor Determining the Cyclic Stability of the Graphite Anode in Potassium-Ion Batteries.

Graphite is the most commonly used anode material for not only commercialized lithium-ion batteries (LIBs) but also the emerging potassium-ion batteries (PIBs). However, the graphite anode in PIBs using traditional dilute ester-based electrolyte systems shows obvious capacity fading, which is in contrast with the extraordinary cyclic stability in LIBs. More interestingly, the graphite in concentrated electrolytes for PIBs exhibits outstanding cyclic stability.

Mechanistic Insight into Ultrafast Kinetics of Sodium Cointercalation in Few-Layer Graphitic Carbon.

Fast-charging sodium ion batteries remain deeply challenged by the lack of suitable carbonaceous anodes that exhibit intercalation plateau with fast kinetics. Here we develop a few-layer graphitic carbon with nanoscale architecture, which enables shortened Na ion diffusion path and fast formation of fully intercalated phase at the same time. Combined in situ Raman and electrochemical test reveal that this graphitic carbon with highly crystalline few layers follows surface-controlled intercalation rather than typical diffusion-controlled kinetics observed in natural graphite.

Enhancing PAPR and Throughput for DFT-s-OFDM System Using FTN and IOTA Filtering.

High frequency wireless communication aims to provide ultra high-speed transmissions for various application scenarios. The waveform design for high frequency communication is challenging due to the requirements for high spectrum efficiency, as well as good hardware compatibility. With high flexibility and low peak-to-average power ratio (PAPR), discrete Fourier transformation spreading-based orthogonal frequency division multiplexing (DFT-s-OFDM) can be a promising candidate waveform.

Polyvinylpyrrolidone-Bridged Prussian Blue/rGO Composite as a High-Performance Cathode for K-Ion Batteries.

Prussian blue (PB) is a very promising cathode for K-ion batteries but its low electronic conductivity and deficiencies in the framework aggravate electrochemical performances. Compositing with conductive reduced graphene oxide (rGO) is an effective solution to address this problem. Nevertheless, little attention was paid to the loss of oxygen-containing functional groups on the rGO substrate during the compositing process, which weakens the interaction between PB and rGO and leads to poor electrochemical performance of PB/rGO.

A highly concentrated electrolyte for high-efficiency potassium metal batteries.

We report a highly concentrated electrolyte consisting of 4 M potassium bis(fluorosulfonyl)imide (KFSI) in diethylene glycol dimethyl ether (DEGDME). This new electrolyte enables stable cycling of K metal anodes with a high CE (over 98% over 400 cycles), and excellent capacity retention (99.7% after 500 cycles) of K||potassium Prussian blue (KPB) batteries.

A Graphite Intercalation Composite as the Anode for the Potassium-Ion Oxygen Battery in a Concentrated Ether-Based Electrolyte.

Nowadays, alkali metal-oxygen batteries such as Li-, Na-, and K-O batteries have been investigated extensively because of their ultrahigh energy density. However, the oxygen crossover of oxygen batteries and the intrinsic drawbacks of the metal anodes (i.e.

Utilizing an autogenously protective atmosphere to synthesize a Prussian white cathode with ultrahigh capacity-retention for potassium-ion batteries.

A facile, low-cost precipitation method, utilizing an autogenously protective atmosphere without the assistance of an inert atmosphere, is proposed to synthesize nano-sized Prussian white K1.62Fe[Fe(CN)6]0.92·0.

Controllable Electrochemical Fabrication of KO-Decorated Binder-Free Cathodes for Rechargeable Lithium-Oxygen Batteries.

Understanding the electrochemical property of superoxides in alkali metal oxygen batteries is critical for the design of a stable oxygen battery with high capacity and long cycle performance. In this work, a KO-decorated binder-free cathode is fabricated by a simple and efficient electrochemical strategy. KO nanoparticles are uniformly coated on the carbon nanotube film (CNT-f) through a controllable discharge process in the K-O battery, and the KO-decorated CNT-f is innovatively introduced into the Li-O battery as the O diffusion electrode.

Molecular Sieve Induced Solution Growth of LiO in the Li-O Battery with Largely Enhanced Discharge Capacity.

The formation of the insulated film-like discharge products (LiO) on the surface of the carbon cathode gradually hinders the oxygen reduction reaction (ORR) process, which usually leads to the premature death of the Li-O battery. In this work, by introducing the molecular sieve powder into the ether electrolyte, the Li-O battery exhibits a largely improved discharge capacity (63 times) compared with the one in the absence of this inorganic oxide additive. Meanwhile, XRD and SEM results qualitatively demonstrate the generation of the toroid LiO as the dominated discharge products, and the chemical titration quantifies a higher yield of the LiO with the presence of the molecular sieve additive.