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Currently widely used carbonate-based electrolytes face difficulty in ensuring that the lithium-ion batteries work beyond 4.2 V for the purpose of energy density improvement. Herein, we report a novel electrolyte that emphasizes the synergistic effect of fluoroethylene carbonate (FEC) and 2-(trifluoromethyl) phenyl boric acid (2-TP) as coadditives, enabling the LiCoO 2 cathode to operate stably under high voltages. With the addition of 1% 2-TP and 10% FEC into a carbonate-based electrolyte, LiCoO 2 shows a significantly improved cyclic stability. Spectral characterizations, electrochemical measurements, and theoretical calculations demonstrate that the improved cyclic stability can be attributed to the cathode−electrolyte interphase (CEI) derived from FEC and 2-TP. These two additives are preferentially oxidized on the LiCoO 2 electrode into their oxidation decomposition products to construct a robust and lowimpedance CEI with inorganic LiF uniformly dispersed in the organic B-containing matrix. This unique CEI construction provides a facile solution to the challenges in developing high-energy-density lithium-ion batteries based on high-voltage cathodes, not limited to LiCoO 2 .

The rate capability of lithium-ion batteries is highly dependent on the interphase chemistry of graphite anodes. Herein, we demonstrate an anode interphase tailoring based on a novel electrolyte additive, lithium dodecyl sulfate (LiDS), which greatly improves the rate capability and cyclic stability of graphite anodes. Upon application of 1% LiDS in a base electrolyte, the discharge capacity at 2 C is improved from 102 to 240 mAh g −1 and its capacity retention is enhanced from 51% to 94% after 200 cycles at 0.5 C. These excellent performances are attributed to the preferential absorption of LiDS and the as-constructed interphase chemistry that is mainly composed of organic long-chain polyether and inorganic lithium sulfite. The long-chain polyether possesses flexibility endowing the interphase with robustness, while its combination with inorganic lithium sulfite accelerates lithium intercalation/deintercalation kinetics via decreasing the resistance for charge transfer.

In this study, polyvinyl alcohol (PVA) is proposed as a new binder to improve the power output of a microbial fuel cell.