Battery for a mobile, whats the difference Polymer v Li-on and which ?

[loncell]

I'm going to swap out my battery as its losing charge quite quick. This ones been in for two years and it has been hammered. I then gets reading and I'm trying to buy like for like but as we know there's no "Original" when it comes to China or even here. I then spots something which I didn't know Lithium Polymer and Li-on batteries. I say this because I was trying to buy one via UK and stock and try get it before Christmas but I noticed in its description is said Polymer. I Googled but am I right thinking its Li-on I need not Polymer?. Mines a fast charging Redmi note 11 pro plus 120w charging.

I did buy one from Ali the best seller and it worked but when I went to charge it said charging but the % never moves off 54. I mauled with the clips re-seating cleaned just the same as soon as I put my old back in it charged.

 

[bmitie]

buy the original dont try and mix and match and polymer loses charge quicker so hence fast charger.

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[loncell]

Thing is every seller says "Original", the last one looked exactly the same as the original that I took out but wouldn't charge.

They can't ship via plane so it's the slow boat from China and I wanted one before the new year.
I've spotted one on eBay and it's near 60% dearer but UK stock. I hate been an old tight wad