Lithium metal is among the most promising anode materials for high-energy batteries due to its high theoretical capacity and lowest electrochemical potential. However, dendrite formation is a major challenge, which can result in fire and explosion of the batteries. Herein, we report on hexadecyl trimethylammonium chloride (CTAC) as an electrolyte additive that can suppress the growth of lithium dendrites by lithiophobic repulsion mechanisms. During the lithium plating process, cationic surfactant molecules can aggregate around protuberances via electrostatic attraction, forming a nonpolar lithiophobic protective outer layer, which drives the deposition of lithium ions to adjacent regions to produce dendrite-free uniform Li deposits. Thus, an excellent cycle of 300 h at 1.0 mA cm–2 and rate performance up to 4 mA cm–2 are available safely in symmetric Li|Li cells. In particular, significantly enhanced cycle and rate performance were achieved when the electrolyte with CTAC additives was used in lithium–sulfur and Li|LiNi0.5Co0.2Mn0.3O2 full cells. The effects of carbon chains, anions of surfactant, and electrostatic repulsion on the deposition of lithium anodes are reported. This work advances research in inhibiting Li dendrite growth with a new electrolyte additive based on cationic surfactants.

Lithium metal is an ideal anode for lithium batteries due to its low electrochemical potential and high theoretical capacity. However, safety issues arising from lithium dendrite growth have significantly reduced the practical applicability of lithium metal batteries. Here, we report the addition of octaphenyl polyoxyethylene as an electrolyte additive to enable a stable complex layer on the surface of the lithium anode. This surface layer not only promotes uniform lithium deposition, but also facilitates the formation of a robust solid-electrolyte interface film comprising cross-linked polymer. As a result, lithium|lithium symmetric cells constructed using the octaphenyl polyoxyethylene additive exhibit excellent cycling stability over 400 cycles at 1 mA cm −2 , and outstanding rate performance up to 4 mA cm −2 . Full cells assembled with a LiFePO 4 cathode exhibit high rate capability and impressive cyclability, with capacity decay of only 0.023% per cycle.

High initial coulombic efficiency is highly desired because it implies effective interface construction and few electrolyte consumption, indicating enhanced batteries life and power output. In this work, ah igh-capacity sodium storage material with FeS 2 nanoclusters ( % 1-2 nm) embedded in N, Sdoped carbon matrix (FeS 2 /N,S-C) was synthesized, the surface of which displays defects-repaired characteristic and detectable dot-matrix distributed Fe-N-C/Fe-S-C bonds.A fter the initial discharging process,t he uniform ultra-thin NaF-rich ( % 6.0 nm) solid electrolyte interphase was obtained, thereby achieving verifiable ultra-high initial coulombic efficiency ( % 92 %). The defects-repaired surface provides perfect platform, and the catalysis of dot-matrix distributed Fe-N-C/Fe-S-Cb onds to the rapid decomposing of NaSO 3 CF 3 and diethylene glycol dimethyl ether successfully accelerate the building of two-dimensional ultra-thin solid electrolyte interphase.D FT calculations further confirmed the catalysis mechanism. As ar esult, the constructed FeS 2 /N,S-C provides high reversible capacity (749.6 mAh g À1 at 0.1 Ag À1 )a nd outstanding cycle stability (92.7 %, 10 000 cycles,1 0.0 Ag À1 ). Especially,a tÀ15 8 8C, it also obtains ar eversible capacity of 211.7 mAh g À1 at 10.0 Ag À1 .A ssembled pouch-type cell performs potential application. The insight in this work provides abright way to interface design for performance improvement in batteries.

No abstract