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[Display omitted] • The bifunctional Li 3 Bi-LiBr protective layer is prepared to stabilize Li 7 P 3 S 11 /Li interface via a simple in-situ reaction. • DFT calculations reveal low surface barrier of Li 3 Bi and high interface energy of LiBr. • Li 3 Bi-LiBr modified Li symmetric cells exhibit increased CCD to 0.838 mA/cm2 and cycle stably at 0.5 mA/cm2 at room temperature. • The modification strategy provides possibility for the application of sulfide electrolyte based ASSLMB. All-solid-state lithium metal batteries (ASSLMBs) are well known as the most promising high-energy-density storage systems. However, the unstable interface between sulfide solid electrolyte and lithium (Li) metal anode limits the application of lithium metal in sulfide-based ASSLMBs. Herein, the bifunctional Li 3 Bi-LiBr protective layer is constructed via a simple in-situ reaction between BiBr 3 and lithium metal to solve the instability issue of the Li 7 P 3 S 11 /lithium interface. The merits of the Li 3 Bi-LiBr protective layer reflect in the low surface barriers of Li 3 Bi and the high interface energy of LiBr by density functional theory (DFT) calculations. The combination of both can effectively promote lithium diffusion and avoid lithium aggregation, thus inhibiting the growth of lithium dendrite. Results show that the Li-LBB/Li 7 P 3 S 11 /LBB-Li symmetric battery exhibits dramatically increased critical current density (0.838 mA/cm2) and long cycling lifespan (over 2000 h at 0.1 mA/cm2 and 0.5 mAh/cm2) at room temperature. In addition, a distinct capacity retention enhancement about 19.03% is embodied in the LiNbO 3 @LiCoO 2 /Li 7 P 3 S 11 /LBB-Li full cell. [ABSTRACT FROM AUTHOR]

In this work, the effectiveness of dual-additives electrolyte consisting of iodine and caffeic acid (noted as CA@I) in improving electrochemical performance has been demonstrated both experimentally and theoretically. The full cell with a high LiFePO 4 loading (17.4 mg cm−2, 3.0 mAh cm−2) has successfully demonstrated a stable lifetime of more than 370 cycles with a capacity retention of 95.0%. [Display omitted] • A novel iodine and caffeic acid dual-additive electrolyte was proposed for Li metal batteries. • I 3 −/I− redox couple can rejuvenate inactive lithium and be revived itself at the cathode side. • The anionic polymerised caffeic acid modulates composition and improve stability of SEI. • The modified Li|Li battery achieves an ultra-long cyclelife over 7000 h at 1 mA cm−2. Inactive ('dead') lithium and conventional fragile solid-electrolyte interphase (SEI) usually cause performance degradation and safety hazards in Li-metal batteries. Recovering inactive lithium and constructing stable SEI are urgently required to enhance the capacity and lifespan of lithium metal batteries. Herein, we have designed a novel dual-additives electrolyte containing an I 3 −/I− redox couple for reviving the inactive lithium, and caffeic acid (CA) that can be anion-polymerised to modulate the composition and improve stability of the SEI. It's found that the generated I 3 −/I− redox couple can turn the inactive Li 2 O into soluble Li+, and prompt the formation of SEI composed of inorganic LiI, Li 3 N and organic RCOOLi with high stability. Density functional theory (DFT) calculations indicate that the diffusion potential barrier of Li+ is significantly lower on the LiI-rich SEI interface, which can not only accelerate the transport of Li+ at the interface, but also effectively prevent I 3 − from attacking Li metal. Benefiting from this elaborate dual-additives electrolyte design, the symmetrical-cells present a superior electrochemical performance, i.e., high critical current density up to 10 mA cm−2, ultra-long lifespan over 7000 h at 1 mA cm−2, and over 2500 cycles under harsh conditions of high temperature (50 °C) and high current density (5 mA cm−2). In addition, as a proof of concept for practical applications of Li-metal batteries, Li|LiFePO 4 full cell delivers excellent cycle stability and rate performance with low hysteresis voltage at a high cathode loading of 17.4 mg cm−2. [ABSTRACT FROM AUTHOR]

[Display omitted] • The rationality of Li deposition under chlorinated SEI was clarified by DFT. • A stable chlorinated hybrid SEI layer has been designed on the Li metal surface. • The enriched LiCl inhibits the growth of Li metal on SEI surface. • LFP|Li cells exhibit longer lifespan under ultrahigh loads (17.4 mg cm−2). Lithium (Li) metal is the ultimate anode material for use in next-generation batteries in the pursuit of higher energy densities. However, the traditional solid electrolyte interphase (SEI) owns the disadvantages of large interfacial impedance, low Li ions migration rate and easy fragility. Herein, this is the first report that reveals in detail the rationality of Li deposition beneath the chlorinated hybrid layer and fast ion transport kinetics at LiCl/Li interface through density functional theory (DFT) estimation. Based on this, an artificial SEI layer enriched with LiCl, LiZn alloy and in-situ ring-opening polymerization of poly(tetrahydrofuran) (PTMG) is constructed on lithium metal surface. The glow-discharge optical emission spectroscopy (GD-OES) results revealed that LiCl is mainly enriched on the surface of the artificial SEI, its excellent electron-blocking ability could inhibit the electron flow tunneling from the Li metal to SEI, which prevents the generation of Li0. As expected, the Li metal anode with an artificial chlorinated hybrid SEI layer exhibits excellent cycle performance over 2000 h with lower overpotential of 11 mV at 1 mA cm−2. Moreover, full-cell delivers higher capacity retention and coulombic efficiency after long cycles under high LiFePO 4 loading (at 17.4 mg cm−2, 3.0 mAh cm−2). [ABSTRACT FROM AUTHOR]