Direct regeneration of degraded lithium-ion battery cathodes with a multifunctional organic lithium salt

Abstract

The recycling of spent lithium-ion batteries is an effective approach to alleviating environmental concerns and promoting resource conservation. LiFePO4 batteries have been widely used in electric vehicles and energy storage stations. Currently, lithium loss, resulting in formation of Fe(III) phase, is mainly responsible for the capacity fade of LiFePO4 cathode. Another factor is poor electrical conductivity that limits its rate capability. Here, we report the use of a multifunctional organic lithium salt (3,4-dihydroxybenzonitrile dilithium) to restore spent LiFePO4 cathode by direct regeneration. The degraded LiFePO4 particles are well coupled with the functional groups of the organic lithium salt, so that lithium fills vacancies and cyano groups create a reductive atmosphere to inhibit Fe(III) phase. At the same time, pyrolysis of the salt produces an amorphous conductive carbon layer that coats the LiFePO4 particles, which improves Li-ion and electron transfer kinetics. The restored LiFePO4 cathode shows good cycling stability and rate performance (a high capacity retention of 88% after 400 cycles at 5 C). This lithium salt can also be used to recover degraded transition metal oxide-based cathodes. A techno-economic analysis suggests that this strategy has higher environmental and economic benefits, compared with the traditional recycling methods.

The Foreseeable Future of Spent Lithium-Ion Batteries: Advanced Upcycling for Toxic Electrolyte, Cathode, and Anode from Environmental and Technological Perspectives

“…SEM detection showed the volumes of rudimentary granules in up-NCM622 became swollen compared with those of D-NCM111, implying that rudimentary granules grew in the upcycling process. Moreover, Liang et al 35 directly regenerated spent Li x FePO 4 (LFE) active substances using 3,4-dihydroxybenzonitrile dilithium (Li 2 DHBN). Excellent combination ability of Li 2 DHBN functional groups with spent LFE materials enhanced the repair process for lithium-defect sites at a high temperature.…”

“…Tackling the above problems has become the only way to clear the obstacles to cathode recovery, but the direct lithium regeneration technology has greatly solved them. 35 Except for efficient utilization of cathode materials, the high-value conversion of anode materials and electrolytes is also a direction worthy of research, so as to achieve full component recovery of spent LIBs. 26,36,37 However, the prominent problems of high energy consumption and low recovery efficiency of complex recovery processes restrict the recycling of anode/electrolyte.…”

Easily recyclable lithium‐ion batteries: Recycling‐oriented cathode design using highly soluble LiFeMnPO4 with a water‐soluble binder

“…Recycling 1 tonne of LiFePO 4 cells using modern recycling methods would require 10 kL of 1 M HCl, 10 kL of 1 M H 2 O 2 , and 54.73 kJ of energy, with a projected cost of ∼$2400 (16,400 Chinese yuan [CNY]). The primary recovered material would be approximately 55 kg of Li 2 CO 3 , valued at ∼$3400 (23,600 CNY) at the current market price 9–12 . Unfortunately, recycling LiFePO 4 may become commercially unviable with labor and processing costs, as the profitability is strongly linked to the lithium salts' market price.…”

Upcycling of Spent LiCoO2 Cathode to Lithium Dual‐Ion Battery Anode

“…Numerous reports are available that emphasize the criticality of cobalt and highlight the merits and demerits of various recovery approaches. [25][26][27][28][29] LCO has been upcycled [30][31][32] to different forms to find its niche in a wide range of applications, including solid lubricant additive, [33] anodes for batteries and pseudocapacitors, [34][35][36][37] photo-and electro-catalysis, etc. [38,39] Since, pristine Co 3 O 4 is well explored as electrode material for metal ion batteries, supercapacitors, and metal-air batteries, cobalt, when upcycled to its oxide form, holds great potential in numerous applications.…”