Li2(BH4)(NH2) Nanoconfined in SBA-15 as Solid-State Electrolyte for Lithium Batteries

Abstract

Solid electrolytes with high Li-ion conductivity and electrochemical stability are very important for developing high-performance all-solid-state batteries. In this work, Li2(BH4)(NH2) is nanoconfined in the mesoporous silica molecule sieve (SBA-15) using a melting–infiltration approach. This electrolyte exhibits excellent Li-ion conduction properties, achieving a Li-ion conductivity of 5.0 × 10−3 S cm−1 at 55 °C, an electrochemical stability window of 0 to 3.2 V and a Li-ion transference number of 0.97. In addition, this electrolyte can enable the stable cycling of Li|Li2(BH4)(NH2)@SBA-15|TiS2 cells, which exhibit a reversible specific capacity of 150 mAh g−1 with a Coulombic efficiency of 96% after 55 cycles.

Recent Development in Nanoconfined Hydrides for Energy Storage

“…A series of notable advances have been observed for complex hydrides as well, although their details are beyond the scope of this review. In short, metal tetrahydridoaluminates/alanates [14,51]: LiAlH 4 [54,81,96,99,101,111,113,135,166,178], NaAlH 4 [33,45,50,69,74,82,[127][128][129]167,214,234,235], tetrahydridoborates/borohydrides [3,12,14,42]: LiBH 4 [42,45,47,54,56,70,78,81,87,89,91,93,99,100,104,106,108,120,123,130,…”

“…Although some complex hydride materials (e.g., complex metal borohydrides) are plagued by an undesirable reaction with the porous host above the hydride melting temperature with formation of silicates [16], mesoporous silica is still used in several studies concerning nanoconfinement effects in hydrogen storage materials [74,[87][88][89][90] (Table 1).…”

“…Although some complex hydride materials (e.g., complex metal borohydrides) are plagued by an undesirable reaction with the porous host above the hydride melting temperature with formation of silicates [16], mesoporous silica is still used in several studies concerning nanoconfinement effects in hydrogen storage materials [74,[87][88][89][90] (Table 1). When LiBH 4 was used as borohydride source in a mesoporous silica host, the reaction occurring during borohydride melting is a two-step process yielding lithium metasilicate, Li 2 SiO 3 , and ultimately lithium orthosilicate, Li 4 SiO 4 (Equation ( 1)) [16].…”

“…tetrahydridoborates/borohydrides [3,12,14,42]: LiBH4 [42,45,47,54,56,70,78,81,87,89,91,93,99,100,104,106,108,120,123,130,134,135,161,216,[230][231][236][237][238][239][240],…”