Li Alginate-Based Artificial SEI Layer for Stable Lithium Metal Anodes

Abstract

Lithium metal anodes (LMAs) are critical for high-energy-density batteries such as Li–S and Li–O2 batteries. The spontaneously formed solid electrolyte interface on LMAs is fragile, which may not accommodate the cyclic Li plating/stripping. This usually will result in a low coulombic efficiency (CE), short cycle life, and potential safety hazards induced by the uncontrollable growth of lithium dendrites. In this study, we fabricate a Li alginate-based artificial SEI (ASEI) layer that is chemically stable and allows easy Li ion transport on the surface of LMAs, thus enabling the stable operation of lithium metal anodes. Compared to bare LMAs, the ASEI layer-protected LMAs exhibit a more stable Li plating/stripping behavior and present effective dendrite suppression. The symmetric Li∥Li cells with the ASEI layer-protected LMAs can stably run for 850 and 350 h at current densities of 0.5 and 1 mA cm–2, respectively. Additionally, the LiFePO4∥Li full cell with the ASEI layer-protected LMA exhibits a capacity retention of about 94.0% coupled with a CE of 99.6% after 1000 cycles at 4 C. We believe that this study of engineering an ASEI brings a new and promising approach to the stabilization of LMAs for high-performance lithium metal batteries.

Challenges and Strategy on Parasitic Reaction for High‐Performance Nonaqueous Lithium–Oxygen Batteries

“…[317] However, there are many challenges for lithium anode: i) the effects of contaminants and superoxide radicals; ii) extremely high chemical reactivity with electrolyte; iii) the growth of Li dendrite, which bring about the consumption of Li metal, poor cycle performance, and even early cell death. [318] In order to overcome those obstacles, a number of strategies have been reported to inhibit the growth of lithium dendrites and stabilize the Li metal anode, including tailoring the anode components, [319][320][321] building artificial anode-electrolyte interfaces, [222,322,323] and optimizing current collectors [324][325][326] and separators. [327][328][329] These approaches are intended to enhance the stability of Li metal anode and significantly improve the electrochemical performance, thus achieving highly efficient, high-rate, and long-lifespan Li-O 2 batteries.…”

“…In order to overcome those obstacles, a number of strategies have been reported to inhibit the growth of lithium dendrites and stabilize the Li metal anode, including tailoring the anode components, [ 319–321 ] building artificial anode–electrolyte interfaces, [ 222,322,323 ] and optimizing current collectors [ 324–326 ] and separators. [ 327–329 ] These approaches are intended to enhance the stability of Li metal anode and significantly improve the electrochemical performance, thus achieving highly efficient, high‐rate, and long‐lifespan Li–O 2 batteries.…”

Lithium Metal Interface Modification for High‐Energy Batteries: Approaches and Characterization

“…To enhance the stability of lithium metal anodes, methods have been introduced to protect the Li metal by constructing an artificial SEI layer using an ex situ method consisted of organic or inorganic materials. [47,[172][173][174][175][176][177][178] Ex situ SEI layer formation refers to the pre-forming of an artificial SEI layer on the lithium metal surface before assembling the cell.…”

Effective suppression of lithium dendrite growth using fluorinated polysulfonamide-containing single-ion conducting polymer electrolytes

“…However, it has been proved that the native SEI layer induced by electrolytes is unstable, which can then tolerate chemical heterogeneity, inducing heterogeneous electrodeposition and generating dendrite growth. 11…”

“…[7][8][9] A native solid electrolyte interface (SEI) layer between the liquid electrolyte and the lithium metal can spontaneously shape up due to the high reactivity of the electrolyte solvent, such as cyclic carbonate (e.g., ethylene carbonate, EC) and cyclic ether (e.g., 1,3-dioxolane, DOL). But the native SEI layer exhibits low ionic conductivity (4.2 Â 10 À8 S cm À1 ), 10 structural instability and chemical heterogeneity, 11 which induce heterogeneous electrodeposition resulting in dendrite growth. Many studies have disclosed various measures such as use of solid electrolytes or gel electrolytes, 4,8,[12][13][14][15][16] construction of an artificial solid electrolyte interface (SEI) layer, [17][18][19][20][21][22][23]54 design of functionalized separators, [24][25][26][27][28][29][30] and improvement of the structure of current collectors 2,[31][32][33][34][35][36][37] to suppress the formation and growth of lithium dendrites.…”