Li2CO3 induced stable SEI formation: An efficient strategy to boost reversibility and cyclability of Li storage in SnO2 anodes

Abstract

The unstable interfaces between a SnO 2 anode and an electrolyte in a Li-ion battery dramatically impair the reversibility and cycling stability of lithiation and delithiation, resulting in low roundtrip Coulombic efficiency (CE) and fast capacity decay of SnO 2 -based anode materials. Herein, a simple strategy of modifying the solid electrolyte interphase (SEI) is developed to enhance the interfacial stability and lithium storage reversibility of SnO 2 by compositing it with graphite (G) and an inorganic component of the SEI, such as Li 2 CO 3 or LiF, which results in the SnO 2 -Li 2 CO 3 /G and SnO 2 -LiF/G composite anodes with high CEs, large capacities and long cycle lives. Specifically, the SnO 2 -Li 2 CO 3 /G composite anode exhibits an average initial CE of 79.6%, a stable reversible capacity of 927.5 mA h g −1 at a current rate of 0.2 A g −1 , and a charge capacity over 1200 mA h g −1 with a CE >99% after 900 cycles at a higher current rate of 1 A g −1 . It is revealed that Li 2 CO 3 induces the formation of a dense and stable SEI on SnO 2 grains and inhibits the coarsening of nanosized Sn particles generated from the dealloying reaction in the SnO 2 -Li 2 CO 3 /G electrode. Moreover, the CE and cycling stability of other alloying-type (Si) and conversion reaction (MnO 2 and Fe 3 O 4 ) anodes can also be greatly promoted by simply milling with Li 2 CO 3 . Thus, a universal and simple strategy is developed to achieve highly reversible and stable electrodes for large-capacity lithium storage.

Insight into Reversible Conversion Reactions in SnO2‐Based Anodes for Lithium Storage: A Review

“…meet well the criteria of higher capacity and safer potentials toward Li storage but still suffer from unsatisfactory reversibility and stability. [ 10–12 ] The difficulty of Li 2 O decomposition is a great obstacle limiting the utilization of metal oxide anodes. And the reverse conversion reaction (M + Li 2 O → MO x ) has become the emphasis of a large number of peer‐reviewed articles in recent years.…”

“…And the reverse conversion reaction (M + Li 2 O → MO x ) has become the emphasis of a large number of peer‐reviewed articles in recent years. [ 9–15 ] As a typical transition metal oxide (TMO), tin dioxide (SnO 2 ) is highly valued due to its high gravimetric capacities and moderate operating potentials. [ 13–16 ] It has been widely demonstrated that conversion around 1.0 V, and an alloying around 0.5 V, would happen during the electrochemically lithiaiton process of SnO 2 , successively contributing the capacity of 711 and 783 mA h g −1[ 16,17 ] $$\[ \begin{array}{*{20}{c}}{{\rm{Sn}}{{\rm{O}}_2} + 4{\rm{L}}{{\rm{i}}^ + } + 4{{\rm{e}}^ - } \to {\rm{Sn}} + 2{\rm{L}}{{\rm{i}}_2}{\rm{O}}}\end{array} \]$$ $$\[ \begin{array}{*{20}{c}}{{\rm{Sn}} + {\rm{xL}}{{\rm{i}}^ + } + {\rm{x}}{{\rm{e}}^ - } \leftrightarrow {\rm{LixSn}}}\end{array} \]$$…”

“…And the reverse conversion reaction (M + Li 2 O → MO x ) has become the emphasis of a large number of peer-reviewed articles in recent years. [9][10][11][12][13][14][15] As a typical transition metal oxide (TMO), tin dioxide (SnO 2 ) is highly valued due to its high gravimetric capacities and moderate operating potentials. [13][14][15][16] It has been widely demonstrated that conversion reaction (I) around 1.0 V, and an alloying reaction (II) around 0.5 V, would happen during the electrochemically lithiaiton process of SnO 2 , successively contributing the capacity of 711 and 783 mA h g −1 [16,17] SnO 4Li 4e Sn 2Li O Although SnO 2 anode has a high specific capacity of 1494 mA h g −1 , it suffers from all the issues that the alloy and conversion anodes face.…”

Highly Crystallized Tin Dioxide Microwires toward Ultraviolet Photodetector and Humidity Sensor with High Performances

“…As one of the most extensively investigated metal oxides, tin dioxide (SnO 2 ) is a very promising n-type semiconducting material with numerous advantages, [1][2][3][4] such as direct and wide bandgap (E g ≈ 3.6 eV), high exciton binding energy (≈130 meV), high carrier concentrations (≈10 20 cm −3 ), superior electron transport properties and high stability in harsh environmental conditions, enabling it to be an attractive material candidate for a wide range of potential applications, for example, chemical and gas sensors, [3,4] transparent conductive electrodes, [4,5] electrocatalysts, [6,7] solar cells, [8,9] lithium-ion batteries, [10,11] field emitters [12] as well as UV photodetectors (PDs). [13,14] Various preparation technologies, such as sol-gel method, solvothermal due to the formation of built-in electric field, [26][27][28][29] which can effectively facilitate the separation of photogenerated electronhole pairs without external power source (i.e., self-power) and allows the device to work independently and sustainably in a non-energy consumption mode.…”

Multiscale Observations of Inhomogeneous Bilayer SEI Film on a Conversion‐Alloying SnO2 Anode

“…[19,20] Tin dioxide (SnO 2 ), as a typical conversionalloying electrode, offers a high theoretical capacity of 1494 mA h g -1 within 0.4-1.0 V versus Li/Li + . [21][22][23] Therefore, it has been considered as an important candidate anode and can ensure both greater energy density and higher safety for LIBs. [24,25] And especially, as the SnO 2 -based anodes tested in 0.01-3.0 V, great progress has been made in achieving large capacity and superior cycling stability.…”