Optimized Cycle and Safety Performance of Lithium–Metal Batteries with the Sustained‐Release Effect of Nano CaCO₃

Abstract

the cycling of the Li metal anode, it is difficult for the conventional electrolyte to form stable and homogeneous solid electrolyte interphase (SEI) layer on the electrode to protect the interface, and the consequent incomplete SEI will further induce the growth of Li dendrites and finally cause cell failure. [7,8] Poor recyclability and serious safety problems have greatly hindered the commercialization of LMBs.So far, tremendous efforts have been invested to inhibit the growth of Li dendrites and boost the Coulombic efficiency (CE) of LMB, multiple methods such as constructing artificial SEI, [9] using 3D porous current collectors, [10] modifying separators, [11,12] optimizing electrolyte composition and forming Li-based alloys have been adopted. [13][14][15] From the perspective of commercialization potential, electrochemical performance, and environmental protection, adding the appropriate amount of additives to commercial carbonate electrolytes is undoubtedly the most advantageous way to optimize the performance of LMBs. [16] To date, additives like some sulfur-containing compounds, [17] inorganic salts, [18][19][20] and fluorine-containing materials [21,22] have been found with high Li-metal compatibility and proved effective in forming stable SEI layer. Nevertheless, most additives will preferentially participate in the interfacial reactions that cause their concentration to drop, leading to the gradual failure of the additives during cycling. [23] It should be noted that increasing the dosage of additives will not only raise the cost, but also accelerate the unfavored side reactions due to the increased concentration of unstable active groups (such as -F, -S(O) 2 -, etc.) and higher viscosity, leading to electrolyte deterioration and gas production (Figure 1a). [24,25] To conquer the above issues, several LiNO 3containing additives have been successfully developed recently inspired by the sustained-release strategy, and their impressive performances demonstrate the great application potential of this method. [26,27] Therefore, optimizing the overall performance and cost of additives designed based on this strategy is of great research significance.Herein, we adopt cheap, environment-friendly CaCO 3 nanoparticles (40-80 nm) as a novel solid additive for LMBs. The added nano CaCO 3 additive exhibits a unique sustainedrelease mechanism as is shown in Figure 1b, which can absorb the decomposition by-products of electrolyte continuously and release active substances containing LiPO 2 F 2 and Ca 2+ , thus

Modified lithium metal anodeviaanion-planting protection mechanisms for dendrite-free long-life lithium metal batteries

“…This indicated that the original driving force for the electrochemical reactions could be decreased to induce a better nucleating effect with a lower overpotential. 61,62 The improvement in the interfacial reaction kinetics was also demonstrated in the electrochemical Li deposition results in Fig. 5e.…”

“…8a-blank, the peaks at 284.8, 286.6, 288.8, 290.2, and 292.9 eV corresponded to hydrocarbon (C-C/C-H), polyether carbon (C-O), carbonyl group (C]O), carbonate (Li 2 CO 3 ), and organic uoride (C-F), respectively. 60,[62][63][64][65] The difference in surface composition between the two samples can be clearly observed as more organic components (C-C, C-O, and Li 2 CO 3 ) existed in the SEI of the bare Li anode, which should mainly arise from the decomposition products of the electrolyte solvents. 64,65 In addition, the small amount of C-F present was from the widespread electrochemical decomposition or interfacial adsorption of these anions in lithium salts (LiTFSI, LiD-FOB).…”

MXene/ZnO flexible freestanding film as a dendrite-free support in lithium metal batteries

“…Lithium will preferentially deposit at the tips of these creases, resulting in uneven lithium deposition and the formation of lithium dendrites. 10,44 In contrast, the MXene/ZnO lm showed no observable change aer being rolled and unrolled, displaying its excellent exibility and strong toughness, which is favorable for cell assembly during the folding or rolling process and for uniform lithium deposition.…”

Molecular/Ionic Designs in the Electrolyte and Interphases for Lithium Metal Anode

“…[48,49] Numerous research groups implement ionic or molecular protective coatings at the tips, which can shield the strong local electrical field and prevent Li metal deposition at the tips. [48][49][50][51] Also, there are local temperature hotspots at these tips. The presence of local hot spots will also result in the concentration of Li + , which promotes the formation of Li dendrites even more.…”