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Despite good compatibility with Li metal, garnet solid electrolytes suffer from severe electron-attack-induced Li-metal penetration and large interfacial resistance. Here, a formic acid (HCOOH)-induced electron-blocking and lithiophilic interlayer is created via a spontaneous reaction with surface Li 2 CO 3 contamination on the garnet electrolyte (LLZTO) pellet. Unlike previous methods that involved immersing LLZTO in acidic solutions, this study employs a volatile small-molecule organic acid that is easily removable, condensed, and recyclable, thus circumventing the environmental drawbacks associated with acid waste. The Li symmetric cell assembled with HCOOH-treated LLZTO exhibits a low interfacial impedance (3 Ω cm 2 ) and a high critical current density (1.7 mA cm -2 ) at room temperature, enabling the cell to cycle continuously for over 1000 h at 0.2 mA cm -2 . Furthermore, under a stacking pressure of 2 MPa, stable lithium plating/stripping was achieved at a current density of 0.3 mA cm -2 with the assistance of HCOOH treatment. Additionally, the battery paired with a LiFePO 4 cathode delivers a high capacity of 151.7 mAh g -1 at 1 C and maintains 88.5% of the initial capacity after 500 cycles, suggesting the feasibility of this interfacial engineering strategy for garnet-based solid Li-metal batteries.

Photonic edge mode confining light in cavities of surface plasmons is beneficial in image and biosensor applications. In the terahertz band, however, the edge mode in a cavity of spoof localized surface plasmons has not matured sufficiently. Herein, a cost-effective strategy to achieve a terahertz photonic edge mode using a metasurface of strongly coupled fourfold spoof localized surface plasmons in a tetramer layout is demonstrated. The quality factors of edge modes decrease when the tetramer shrinks, as revealed by the terahertz dielectric functions. The edge modes that emerge can be categorized as inner and outer edge modes, as deduced from the simulated electric field distribution. Our results show that the edge modes are due to the interaction of spoof localized surface plasmons in the terahertz band.

Conventionally, a symmetry-protected quasi bound state of the continuum (BIC) becomes achievable by breaking the C 2 symmetry of meta-atoms. Our work exhibits a novel approach to achieving dual band quasi-BIC by breaking the C 2v symmetry into C s symmetry. Also, we show that a single band quasi-BIC can be achieved by breaking the C 2v symmetry into C 2 symmetry. Our metasurface of C 2v symmetry is composed of double gaps split ring resonator (DSRR), and it degrades to C 2 symmetry when the double gaps are displaced in opposite directions. One band quasi-BIC can be observed occurring at around 0.36 and 0.61 THz respectively with the metasurface excited by x- and y-polarized terahertz radiation, respectively. A couple of dark dipole oscillator dominates the quasi-BIC at 0.36 THz, while a quadruple-like oscillator dominates the quasi-BIC at 0.61 THz. The damping ratio and coupling coefficients of the above single quasi-BIC are close to the orthogonal polarization of the incident terahertz wave. However, the metasurface of the DSRR array degrades down to C s symmetry when the double gaps are displaced in the same directions. A dual band quasi-BIC (0.23 THz and 0.62 THz) is found to be sensitive to the y-polarized terahertz radiation. It is found that the inductive-capacitive (LC) resonance results in quasi-BIC at 0.23 THz, while a quadrupole-like oscillation results in quasi-BIC at 0.62 THz. The quasi-BIC at 0.62 THz has a higher coupling coefficient and lower damping ratio than quasi-BIC at 0.23 THz in a metasurface of C s symmetry. The realization of the above locally symmetric breaking on the quasi-BIC of terahertz metasurfaces is helpful for the innovation of multi-band terahertz biosensors.