The cost-effective manganese-based spinel oxide LiMn₂O₄ (LMO) is a promising cathode material for large-scale applications in all-solid-state lithium batteries (ASSLBs). However, the gravimetric energy density of all-solid-state lithium pouch batteries (ASSLPBs) with conventional catholyte-based composite cathodes containing LMO is only about 256.8 Wh kg^–1, far below the target value of 500 Wh kg^–1, and the Jahn-Teller distortion leads to poor cycling stability. To address this issue, the study proposes replacing the inert catholyte with an active halide cathode Li₃TiCl₆ (LTC) and combining it with the low-cost LMO cathode to form a design of catholyte-free composite cathodes. During deep charge and discharge cycles, the Ti in LTC inserts into the lattice of LMO, which both improves the discharge specific capacity of the catholyte-free composite cathode to 316.3 mAh g^–1 and extends the cycling life by reducing the Jahn-Teller distortion. As a result, the gravimetric energy density of the ASSLPB with the catholyte-free composite cathode reaches 588.8 Wh kg^–1, which is 2.3 times higher than that of conventional catholyte-based composite cathodes. Therefore, the design of the catholyte-free composite cathode effectively solves the issues of insufficient energy density and short cycling life of low-cost LMO cathodes in large-scale applications.

CsPbI₂Br-based perovskite solar cells (PSCs) have attracted much attention because of their excellent phase stability and appropriate bandgap. However, numerous defects of undercoordinated ions or mobile species are the sites of carrier nonradiative recombination, causing a low power conversion efficiency (PCE). In this work, NaCl and nitrogen-doped graphene quantum dots (N-GQDs) as binary additives are introduced into perovskite precursor to obtain high-quality photoactive films. Chloride ion (Cl⁻) is incorporated into perovskite due to the same physical and chemical properties as bromine (Br⁻), that align the energy level of CsPbI₂Br, decrease the energy barrier between perovskite and P3HT to promote carrier transport and extraction, hence result in the reduced energy loss. Meanwhile, because of its good conductivity, N-GQDs at grain boundaries can rapidly conduct photogenerated electrons to SnO₂, suppressing carrier recombination at grain boundaries. Furthermore, the trap state density of the CsPbI₂Br film with binary additives is reduced, which could prolong the carrier lifetime, and improve surface morphology. As a result, a PCE of 15.37% for CsPbI₂Br PSCs with binary additives is obtained，which shows ∼22.76% relative increment compare with the pristine PSCs. Therefore, a simple and convenient optimization strategy of binary additives for PSCs is proposed in this work.