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The nickel-rich cathode LiNi0.8Co0.1Mn0.1O2 (NCM811) is deemed as a prospective material for high-voltage lithium-ion batteries (LIBs) owing to its merits of high discharge capacity and low cobalt content. However, the unsatisfactory cyclic stability and thermostability that originate from the unstable electrode/electrolyte interface restrict its commercial application. Herein, a novel electrolyte composed of a polyethylene (PE) supported poly­(vinylidene fluoride-co-hexafluoropropylene) (P­(VdF-HFP)) based gel polymer electrolyte (GPE) strengthened by a film-forming additive of 3-(trimethylsilyl)­phenylboronic acid (TMSPB) is proposed. The porous structure and good oxidative stability of the P­(VdF-HFP)/PE membrane help to expand the oxidative potential of GPE to 5.5 V compared with 5.1 V for the liquid electrolyte. The developed GPE also has better thermal stability, contributing to improving the safety performance of LIBs. Furthermore, the TMSPB additive constructs a low-impedance and stable cathode electrolyte interphase (CEI) on the NCM811 cathode surface, compensating for GPE’s drawbacks of sluggish kinetics. Consequently, the NCM811 cathode matched with 3% TMSPB-containing GPE exhibits remarkable cyclicity and rate capability, maintaining 94% of its initial capacity after 100 cycles at a high voltage range of 3.0–4.35 V and delivering a capacity of 133.5 mAh g–1 under 15 C high current rate compared with 68% and 75.8 mAh g–1 for the one with an additive-free liquid electrolyte. By virtue of the enhanced stability of the NCM811cathode, the cyclability of graphite||NCM811 full cell also increases from 48 to 81% after 100 cycles. The incorporation of P­(VdF-HFP)-based GPE and TMSPB electrolyte additive points out a viable and convenient pathway to unlock the properties of high energy density and satisfactory safety for next-generation LIBs.

As an ideal anode material of lithium metal for highenergy-density batteries, the development of lithium metal batteries (LMBs) has been limited by the Li dendrite's growth and accumulation of dead Li. To solve this problem, a highly elastic artificial polymer layer coated on the surface Li anode by rapid ultraviolet radical polymerization is developed. The clad poly-(methyl methacrylate-acrylic acid-sulfobetaine methacrylate) (P-(MMA-AA-SBMA)) terpolymer not only shows good interfacial compatibility with Li metal due to the surface formation process by in situ light solidification but also contains functional anion groups of −COO − and −SO 3 − , contributing the convenient channels to regulate the transport of Li ions. Ascribed from the stable interface of clad Li and the suppressed decomposition reaction of the liquid electrolyte in the later cycle stage, the Li||LiCoO 2 full cell exhibits good cycle stability, maintaining 96% of initial capacity after 100 cycles in 1C rate between 3 and 4.35 V, compared with that of 67% for bare Li. Thus, the artificial polymer cladding promotes the electrochemical stability of Li metal, providing a facile way for application in high-energy-density LMBs.

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