No abstract

Lithium-ion batteries with both low-temperature (low-T) adaptability and high energy density demand advanced cathodes. However, state-of-the-art high-voltage (high-V) cathodes still suffer insufficient performance at low T, which originates from the poor cathode–electrolyte interface compatibility. Herein, we developed a shallow surface Zr-doped and Li+ conductive Li2Zr­(PO4)2 (LZPO) interspersed massage-ball-like LiCoO2 (LZPO-LCO). The surface-interspersed LZPO can induce an electrolyte superwettability of LZPO-LCO, which helps to form a high-quality cathode–electrolyte interphase with strong stability and low interface resistance. Without changing electrolyte, even at a low T of −25 °C and a high V of 4.6 V, LZPO-LCO shows an ultrahigh capacity of ∼200 mAh g–1 at 0.2C and 137 mAh g–1 at 5C, maintaining 94% capacity after 100 cycles with an average Coulombic efficiency of 99.9%. Besides, the fabricated full cells deliver a high energy density of ∼340 Wh kg–1 and maintain 92% capacity after 200 cycles at −25 °C. This work provides a significant leap forward for high-performance low-T cathodes.

Two-dimensional (2D) van der Waals (vdW) materials, featuring relaxed phase-matching conditions and highly tunable optical nonlinearity, endow them with potential applications in nanoscale nonlinear optical (NLO) devices. Despite significant progress, fundamental questions in 2D NLO materials remain, such as how structural distortion affects second-order NLO properties, which call for advanced regulation and in situ diagnostic tools. Here, by applying pressure to continuously tune the displacement of Nb atoms in 2D vdW NbOI 2 , we effectively modulate the polarization and achieve a 3-fold boost of the secondharmonic generation (SHG) at 2.5 GPa. By introducing a Peierls distortion parameter, λ, we establish a quantitative relationship between λ and SHG intensity. Importantly, we further demonstrate that the SHG enhancement can be achieved under ambient conditions by anionic substitution to tune the distortion in NbO(I 1−x Br x ) 2 (x = 0−1) compounds, where the chemical tailoring simulates the pressure effects on the structural optimization. Consequently, NbO(I 0.60 Br 0.40 ) 2 with λ = 0.17 exhibits a giant SHG of over 2 orders of magnitude higher than that in monolayer WSe 2 , reaching the record-high value among reported 2D vdW NLO materials. This work unambiguously demonstrates the correlation between Peierls distortion and SHG property and, more broadly, opens new paths for the development of advanced NLO materials by manipulating the structure distortions.