Low-cost aluminum-graphite batteries utilizing an AlCl 3 /urea ionic liquid analog are promising candidates for grid-scale electricity storage. This work describes the use of N-methyl and N-ethyl derivatives of urea, which yield lower viscosity electrolytes, as a result of a lower ionic concentration. These electrolytes have increased ionic conductivities, and higher discharge voltages due to the differences in concentrations of electroactive species.

Rechargeable lithium metal batteries are next generation energy storage devices with high energy density, but face challenges in achieving high energy density, high safety, and long cycle life. Here, lithium metal batteries in a novel nonflammable ionic‐liquid (IL) electrolyte composed of 1‐ethyl‐3‐methylimidazolium (EMIm) cations and high‐concentration bis(fluorosulfonyl)imide (FSI) anions, with sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) as a key additive are reported. The Na ion participates in the formation of hybrid passivation interphases and contributes to dendrite‐free Li deposition and reversible cathode electrochemistry. The electrolyte of low viscosity allows practically useful cathode mass loading up to ≈16 mg cm−2. Li anodes paired with lithium cobalt oxide (LiCoO2) and lithium nickel cobalt manganese oxide (LiNi0.8Co0.1Mn0.1O2, NCM 811) cathodes exhibit 99.6–99.9% Coulombic efficiencies, high discharge voltages up to 4.4 V, high specific capacity and energy density up to ≈199 mAh g−1 and ≈765 Wh kg−1 respectively, with impressive cycling performances over up to 1200 cycles. Highly stable passivation interphases formed on both electrodes in the novel IL electrolyte are the key to highly reversible lithium metal batteries, especially for Li–NMC 811 full batteries.

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Room temperature ionic liquids (RTILs) are solvent-free liquids comprised of densely packed cations and anions. Properties of Py13Cl–AlCl3 ILs were studied and compared with EMIC-AlCl3 ILs for use as electrolyte in Al–graphite battery.

Repeated clipping and filtering (RCF) is a simple method for reducing the peak-to-average power ratio (PAPR) of the signal in the orthogonal frequency-division modulation (OFDM) system. We propose to modify RCF by limiting the distortion on each tone of the OFDM so that both low PAPR and low error can be achieved. Index Terms-Bounded distortion (BD), clipping and filtering, orthogonal frequency-division modulation (OFDM), peak-to-average power ratio (PAPR).

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