Countering voltage fade and capacity decay of Li-rich layered oxides endowed by a hydridoaluminate additive

The development of cathode materials exhibiting high capacity and superior cycling performance plays a pivotal role in enhancing the energy density of lithium-ion batteries (LIBs). In this context, lithium-rich layered oxides (LLOs) have emerged as leading candidates among cathode materials owing to their exceptionally high specific capacities. However, prolonged cycling induces the detrimental interfacial reactions between LLOs and electrolytes, leading to oxygen release, transition metal dissolution, and structural microcracks, collectively driving progressive voltage fade and capacity deterioration. In this study, lithium tri(tert-butoxy)hydridoaluminate (LTBA) was employed as a functional electrolyte additive to optimize the electrochemical performance of a model Li-rich layered oxide cathode (Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 , denoted as LMNCO). Remarkably, the LTBA-modified LMNCO exhibited a capacity retention of 83.6 % after 300 cycles at 1 C, significantly outperforming the bare electrolyte system (only 45.6 % retention). Notably, the voltage fade in LTBA-modified electrolyte was attenuated to 1.31 mV per cycle, representing a 39.4 % reduction compared to conventional electrolyte (2.16 mV per cycle). The experimental results indicate that the LTBA additive in electrolyte acts as an HF scavenger and moderate reducing agent, preventing transition metals from dissolving in the LMNCO cathode. • LTBA as an electrolyte additive can in-situ form a coating layer on LMNCO. • Cycling stability and voltage decay of LMNCO is significantly enhanced with LTBA. • LTBA can also avoid the dissolution of transition metals in LMNCO cathode.