Defective Boron Nitride Inducing the Lithium‐ion Migration on the Sub‐Surface of LiBH₄

Abstract

The safety issues oflithium-ion batteries provoke the development of highly secure solidelectrolytes. Hydride electrolytes owning the high electrochemical stabilityand anode compatibility may sufficiently relieve theconcerns of safety. However, the low ionic conductivity at room temperature hampersits further application. Herein, the strategy of defect-induced (BH 4 )deformation to achieve high ionicconductivity LiBH 4 /BN composite electrolyte is suggested. The theoreticalcalculations indicate that the volume of the (BH 4 )tetrahedron is expanded by 14%. Such atetrahedron deformation weakens the LiH interaction forces in LiBH 4 , and thus promotes the Li-ion migration. The LiBH 4 /BN composites are enabled to deliver lithium ionicconductivity of 1.15 × 10 -4 S cm -1 at 40 °C with a Li-ion transference number of 97%, persuading an excellent solidelectrolyte for all-solid-state batteries. The subsurface of LiBH 4 offers the lowest migration barrier among all possiblechannels, paving the optimal way for Li-ion migration. Furthermore, the LiBH 4 /BN electrolytes supply excellent electrochemical stabilityand electrode compatibility. The utilized strategy of outfield induction (notonly defects) and ligand deformation (not only (BH 4 ) -) may also be extended to other solid electrolytes.

Polymeric Electronic Shielding Layer Enabling Superior Dendrite Suppression for All-Solid-State Lithium Batteries

“…The XPS data are summarized in Table S2. In the B 1s spectrum of AOLiBHI-0PMMA (Figure 2c), B−H (186.20 eV) 51 was gradually transformed to oxidized BH 4 − (187.50 eV) 52,53 in the first cycle as the potential was increased from 2.8 to 5.0 V. The amount of B−H decreased from 28.13 at% (2.8 V) to 19.39 at% (5.0 V), and this was accompanied by a sharp increase in the amount of oxidized BH 4 − from 32.26 at% (2.8 V) to 51.04 at% (5.0 V). Much worse, in the second and third cycles, the B−H content of AOLiBHI-0PMMA was further reduced and only 13.14 at% remained at 5.0 V after the third cycle, indicating severe oxidation (Figure S3d,f).…”

Engineering the d-Orbital Energy of Metal–Organic Frameworks-Based Solid-State Electrolytes for Lithium–Metal Batteries

“…Li-ion batteries (LIBs) based on the intercalation and deintercalation of Li + ion into cathode have already been utilized as energy storage and conversion systems for electric devices and vehicles. − However, due to a low energy density (below 300 Wh kg –1 ), the current LIBs cannot satisfy the high energy density systems such as long-distance vehicles. − Lithium metal anode can be regarded as a possible candidate due to its high theoretical capacity. − Unfortunately, the flammable organic electrolytes and leakage issues significantly restrict the development of lithium–metal batteries (LMBs). − In response, to alleviate the safety issues, solid-state electrolytes (SSEs), such as oxides, − polymers, − sulfides, − hydride, − and metal–organic frameworks (MOFs), − have been widely reported to achieve high-performance LMBs due to good mechanism modulus and thermal properties. Among the options, MOFs offer great potential for high-performance SSEs due to tunable metal sites and ligand structures. − The variations of chemical components, pore features, and unique channel structures can present excellent prospects for controlling the physicochemical characteristics of MOFs, thereby enabling the pursuit of high-performance SSEs. − Despite the excellent electrochemical stability and high mechanical strength of MOFs as SSEs, the current MOF-based SSEs exhibit relatively low Li + ion conductivity, leading to significant concentration polarization and poor cycling stability.…”

Realizing fast Li-ion conduction of Li3PO4 solid electrolyte at low temperature by mechanochemical formation of lithium-containing dual-shells

“…In addition, the activation energy ( E a ) of lithium-ion mobility can be quantitatively analyzed by linear fitting of the data in Fig. 3b by using Arrhenius eqn (1): 31 where K B stands for Boltzmann's constant and C stands for the constant. The Arrhenius calculation results are shown in Fig.…”

“…4a, the discharge current drops sharply after applying a 10 mV step voltage and then tends to stabilize. The electron conductivity ( σ e ) of the sample is calculated using eqn (2): 31 where I 0 is the steady-state current, d is the electrolyte sheet thickness, U 0 is the applied voltage, and S is the surface area of the electrolyte sheet. The electron conductivity of the sample was calculated to be about 1.176 × 10 −7 S cm −1 , which was about 2 orders of magnitude lower than the conductivity of lithium-ions at the same temperature, and the lithium-ion mobility was determined to be greater than 0.99.…”

“…The LiBH 4 as a fast-ion conductive solid electrolyte was first reported by Matsuo et al, which shows good electrochemical stability and good interface compatibility with electrode materials. 30,31 It was found that the prepared LiBH 4 /Li 3 PO 4 composite had a double-coated structure, namely, LiBO 2 as the intermediate layer to prevent further reaction between LiBH 4 and Li 3 PO 4 , and the amorphous LiBH 4 as an outer layer to provide a continuous ionic conductivity network among Li 3 PO 4 particles to synergistically improve their ionic conductivity. The composites presented an ionic conductivity up to 0.04 mS cm À2 at 75 1C, which is nearly 4 orders of magnitude higher than that of pure Li 3 PO 4 .…”