Key insights into the evolution of lithium-ion batteries: present, future, and hybridized technologies.

Large area and stable mixed-cation perovskite solar modules are fabricated via hybrid-CVD, which represents a step forward towards commercialization.

Besides high efficiency, the stability and reproducibility of perovskite solar cells (PSCs) are also key for their commercialization. Herein, we report a simple perovskite formation method to fabricate perovskite films with thickness over 1 μm in ambient condition on the basis of the fast gas−solid reaction of chlorine-incorporated hydrogen lead triiodide and methylamine gas. The resultant thick and smooth chlorine-incorporated perovskite films exhibit full coverage, improved crystallinity, low surface roughness and low thickness variation. The resultant PSCs achieve an average power conversion efficiency of 19.1 ± 0.4% with good reproducibility. Meanwhile, this method enables an active area efficiency of 15.3% for 5 cm × 5 cm solar modules. The un-encapsulated PSCs exhibit an excellent T80 lifetime exceeding 1600 h under continuous operation conditions in dry nitrogen environment.

An ever-growing demand for high-energy density and high-power Li-ion batteries has driven active research for electrode materials with superior capacity. Recent years have seen the development of Ni-rich transition metal oxide cathode materials due to their high reversible capacity and lower cost. To achieve full capacity from the charge compensation process, a high voltage (>4.4 V) charging is required. However, the battery operation at higher voltages eventually results in dramatic capacity fading and voltage decay with a rapid decomposition of the electrolyte upon further charge-discharge. While previous studies have reported the degradation mechanism within the electrode surface, there have been few empirical investigations into the solid-electrolyte interphase (SEI) formation on Ni-rich cathodes. In the current work, we visualize the different nature of the electrode-electrolyte interphase at various cut-off voltages (2.0-4.2 V, 2.0-4.5 V, and 2.0-4.8 V). We correlate the key properties of the SEI layer with the capacity fading mechanism in the high capacity battery system. The speciation of transition metal elements (Ni, Mn, and Co) into various oxidation and spin states has been identified as the dominant process of the capacity degradation. Fig. 7 (a) Proposed SEI structures/properties at different cut-off voltages with transition metal spin states, crystal structures, schematics of energy vs. density of states (N(E)) diagram, and visualizations of Li + trapping based on the SIMS profile in the Ni-rich transition metal oxide cathode. (b) Correlation between cut-off voltages, lithium diffusivity (D Li ), SEI impedance (R SEI ), and magnetic moment (m B ).

The cathode-electrolyte interphase (CEI) formation between the cathode and the electrolyte is a critical factor that determines the stability of lithium-ion batteries (LiBs). The CEI layer consists of various by-products...